PRECEDENTIAL

UNITED STATES COURT OF APPEALS

FOR THE THIRD CIRCUIT 

_____________

No. 13-1910

_____________

UNITED STATES OF AMERICA

v.

RICHARD STANLEY,

 Appellant 

_____________

On Appeal from the United States District Court

for the Western District of Pennsylvania

District Court No. 2-11-cr-00272-001

District Judge: The Honorable Joy Flowers Conti

Argued January 7, 2014

Before: SMITH, SHWARTZ, and SCIRICA, 

Circuit Judges

(Filed: June 11, 2014 )
2

Donovan J. Cocas [ARGUED]

Rebecca R. Haywood

Office of United States Attorney

700 Grant Street

Suite 4000

Pittsburgh, PA 15219

Counsel for Appellee

Lisa B. Freeland

Peter R. Moyers [ARGUED]

Office of Federal Public Defender

10001 Liberty Avenue

1500 Liberty Center

Pittsburgh, PA 15222

Counsel for Appellant

________________

OPINION

________________

SMITH, Circuit Judge.

Richard Stanley appeals from an order of the

United States District Court for the Western District of 

Pennsylvania denying his motion to suppress evidence 

that he was in possession of child pornography. 

Specifically, Stanley argues that a Pennsylvania State 

Police officer conducted a warrantless search when he

used a device called the “MoocherHunter” to trace 
3

Stanley’s wireless signal from a neighbor’s unsecured 

wireless router to its source inside Stanley’s home. For 

the reasons that follow, we conclude that the use of the 

MoocherHunter was not a search within the meaning of 

the Fourth Amendment. Accordingly, we will affirm the 

judgment of the District Court.1 

I.

On November 11, 2010, Corporal Robert Erdely 

(“Erdely”), the head of the computer crime unit of the 

Pennsylvania State Police (“PSP”), was investigating the 

online distribution of child pornography when he 

discovered a computer on the Gnutella peer-to-peer 

network2sharing 77 files that he suspected contained

child pornography. Based on information available to 

any Gnutella user, Erdely determined that this computer 

was using file-sharing software with a globally unique 

identification number of 

“8754E6525772BA0134C4C6CACF12E300” (“300 

GUID”) and was connected to the Internet via an Internet

 

1

Judge Shwartz joins Parts I through IV.A of this 

Opinion.

2

Peer-to-peer networks allow users to share files by 

connecting to other individual computers directly, without 

using a centralized administrative system. Gnutella is a 

particularly large peer-to-peer network and is utilized by a 

number of popular file sharing programs. 
4

protocol address (“IP address”) of “98.236.6.174” (“174 

IP Address”). 

Through a search of publicly available records,

Erdely determined that the 174 IP Address was registered 

to a Comcast Cable (“Comcast”) subscriber, and he

obtained a court order requiring Comcast to disclose this 

individual’s subscription information. In response, 

Comcast informed Erdely of the subscriber’s name (“the 

Neighbor”) and his home address in Pittsburgh, 

Pennsylvania.

On November 18, 2010, Erdely executed a search 

warrant for the Neighbor’s home. The search revealed 

that none of the Neighbor’s computers contained either 

child pornography or the file-sharing software with the 

300 GUID. The search also revealed that the Neighbor’s 

wireless Internet router was not password-protected. 

From this information, Erdely deduced that the computer 

sharing child pornography was connecting wirelessly to 

the Neighbor’s router from a nearby location without the 

Neighbor’s knowledge or permission.

3

 In other words, 

 

3

To establish a wireless connection, an Internet user 

selects the desired wireless network from a list of available 

options displayed on his wireless-enabled device. This causes 

a wireless card inside the user’s device to transmit radio 

waves to the wireless router, which then transmits radio 

waves back to the device. This exchange of radio waves 
5

Erdely determined that the computer in question was 

“mooching” off the Neighbor’s Internet connection.

With the Neighbor’s permission, Erdely connected 

a police computer to the router in order to determine the 

media access control address (“MAC address”) and 

private IP address of any other devices that were 

connected wirelessly at the time.4 From this data, Erdely 

determined that the mooching computer was not 

connected at that time. With the Neighbor’s permission, 

Erdely left the police computer attached to the router so it

could be accessed remotely from Erdely’s office in 

Harrisburg, Pennsylvania. 

On January 19, 2011, while working in Harrisburg, 

Erdely learned that the computer associated with the 300 

GUID was again sharing child pornography on the IP 

address assigned to the Neighbor. By remotely accessing

the police computer he had left in the Neighbor’s home, 

Erdely determined that the mooching computer had a 

private IP address of “192.168.2.114” (the “114 Private 

IP Address”) and a MAC address of “mac=00-1C-B3-

B4-48-95” (the “95 MAC Address”). Erdely searched 

online for the “mac” prefix in the 95 MAC address and 

discovered that it belonged to an Apple wireless card. 

 

comprises the “wireless signal” that connects the device to the 

router.

4

This information was available to any computer 

connected to the Neighbor's router.
6

Because Erdely had not discovered any Apple wireless 

devices in the Neighbor’s home, this information 

reinforced his conclusion that the 95 MAC Address and 

the 114 Private IP Address belonged to the mooching 

computer. Erdely decided to travel to Pittsburgh so that 

he could use a “MoocherHunter” device to attempt to 

determine this computer’s location. 

The aptly-vernacularized MoocherHunter is a 

mobile tracking software tool that can be downloaded for 

free from the manufacturer’s website and used by anyone 

with a laptop computer and a directional antenna.5 This 

device can be used in either “active mode” or “passive 

mode.” In “passive mode,” the user enters the MAC 

address of the wireless card he wishes to locate and the 

program measures the signal strength of the radio waves 

emitted from this card.6 These signal strength readings 

increase as the user aims the antenna in the direction of 

the mooching computer and moves closer to its location. 

Before using the MoocherHunter, Erdely contacted

an Assistant United States Attorney in the Western 

District of Pennsylvania to discuss the propriety of 

 

5

Though MoocherHunter is the name of the software, 

for the sake of convenience this opinion will refer to this 

software and the equipment using it collectively as “the 

MoocherHunter.”

6

The mechanics of “active mode” are not relevant to 

this appeal. 
7

obtaining a search warrant.7 Erdely and the AUSA had a 

“lengthy discussion” in which they decided that the 

MoocherHunter was “completely different” from the 

infrared technology used in Kyllo v. United States, 537 

U.S. 27 (2001). J.A. 271. They also discussed the

practical impossibility of obtaining a search warrant 

without knowing which one of the many nearby 

residences the signal was being transmitted from. 

Ultimately, Erdely determined that he needed to proceed 

without a warrant.

On the evening of January 19, 2011, Erdely arrived 

at the Neighbor’s home and entered the 95 MAC Address 

into the MoocherHunter. From the residence, he found 

that the MoocherHunter’s readings were strongest (67) 

when he aimed the antenna at a six-unit apartment 

complex across the street. From the public sidewalk in 

front of this building, the MoocherHunter’s readings 

were strongest (100) when Erdely aimed the antenna 

directly at Stanley’s apartment. 

That night, Erdely used this information to obtain a 

search warrant for Stanley’s home. Shortly thereafter, 

Erdely and other PSP officers executed this warrant. 

When these officers arrived, Stanley initially fled through 

a back door. He soon returned, however, and confessed 

 

7

Ederly reached out to the AUSA after unsuccessfully 

attempting to contact an attorney at the Allegheny County 

District Attorney’s Office. 
8

that he had connected to the Neighbor’s router to 

download child pornography. Erdely seized Stanley’s 

Apple laptop and later recovered 144 images and video 

files depicting child pornography.

II.

As a result of Erdely’s meticulous investigation, a 

federal grand jury in the Western District of 

Pennsylvania returned a one-count indictment charging 

Stanley with possession of child pornography in violation 

of 18 U.S.C. § 2252(a)(4)(B). Stanley was arrested and 

initially pled not guilty.

On April 13, 2012, Stanley filed a motion to 

suppress his statements to Erdely and the evidence 

obtained from his home and computer. His primary 

argument was that Erdely conducted a warrantless search 

under Kyllo v. United States, 533 U.S. 27 (2001), when 

he used the MoocherHunter to obtain information about 

the interior of his home that was unavailable through 

visual surveillance.8

On November 14, 2012, the District Court denied 

Stanley’s motion. Citing Smith v. Maryland, 442 U.S. 

 

8

Stanley also argued that Erdely’s search warrant was 

not supported by probable cause and that the MoocherHunter 

was a “mobile tracking device” which required a warrant 

under 18 U.S.C. § 3117. He has abandoned these arguments 

on appeal.
9

735 (1979), the District Court held that Stanley lacked a 

reasonable expectation of privacy in his wireless signal 

because he “exposed his wireless signal to a third party 

and assumed the risk that the signal would be revealed to 

authorities.” J.A. 23. The District Court also rejected 

Stanley’s Kyllo argument, explaining that “although the 

defendant [in Kyllo] caused the heat by using highintensity lamps, he did not send it to a third party and to 

the extent he could, he contained the heat in his garage.” 

Id. at 27. Stanley, on the other hand, “had to . . . initiate 

contact” with the Neighbor’s router and therefore “did 

not have a reasonable expectation of privacy in that 

wireless signal simply because it emanated from a 

computer located inside of his home.” Id. Finally, the 

District Court noted that if Stanley had shared child 

pornography through his own Internet subscription, 

Erdely could have discovered his location the same way 

he discovered the Neighbor’s: by subpoenaing his 

Internet service provider for subscription information. 

Id. at 28. “That [Stanley] established an unauthorized 

connection,” the District Court reasoned, “does not 

convert his subjective expectation of privacy into a 

reasonable one.” Id. 

Thereafter, Stanley entered into an agreement with 

the government, under which he would plead guilty but

reserve the right to appeal the District Court’s order 

denying his motion to suppress. After his guilty plea was 

entered, the District Court sentenced Stanley to 51 
10

months in prison. This timely appeal followed. 

III.

The District Court had subject matter jurisdiction 

pursuant to 18 U.S.C. § 3231. We have jurisdiction 

under 28 U.S.C. § 1291.

“With respect to a suppression order, we review 

the District Court’s factual findings for clear error and 

exercise plenary review over its legal determinations.” 

United States v. Ritter, 416 F.3d 256, 261 (3d Cir. 2005) 

(internal citations omitted).

IV.

“There are two ways in which the government’s 

conduct may constitute a ‘search’ implicating the Fourth 

Amendment.” Free Speech Coal., Inc. v. Att’y Gen. of 

U.S., 677 F.3d 519, 543 (3d Cir. 2012). First, a search

occurs when the government “unlawfully, physically 

occupies private property for the purpose of obtaining 

information.” Id. (citing United States v. Jones, 132 

S.Ct. 945, 949–52 (2012)). Alternatively, a search occurs 

when the government violates an individual’s expectation 

of privacy that “society recognizes as reasonable.” Kyllo, 

533 U.S. at 33 (citing Katz v. United States, 389 U.S. 

347, 361 (1967) (Harlan, J., concurring)).
11

Stanley does not contend that Erdely physically 

trespassed on his property at any point during his 

investigation. Nor would that argument have been 

successful; Erdely did not physically enter Stanley’s 

property until after he obtained a search warrant for the 

apartment. Instead, Stanley argues that Erdely violated 

his reasonable expectation of privacy when he used the 

MoocherHunter to trace Stanley’s wireless signal back to 

the interior of his home.

Determining whether this second type of search

occurred involves two questions: “(1) whether the 

individual demonstrated an actual or subjective 

expectation of privacy in the subject of the search or 

seizure; and (2) whether this expectation of privacy is 

objectively justifiable under the circumstances.” Free 

Speech Coal., Inc., 677 F.3d at 543. To be objectively 

justifiable, a defendant’s expectation of privacy must be 

more than rational; society must be willing to recognize it 

as legitimate. See United States v. Jacobsen, 466 U.S. 

109, 122 (1984) (“The concept of an interest in privacy 

that society is prepared to recognize as reasonable is, by 

its very nature, critically different from the mere 

expectation, however well justified, that certain facts will 

not come to the attention of the authorities.”); Rakas v. 

Illinois, 439 U.S. 128, 143 n.12 (1978) (“Obviously, 

however, a ‘legitimate’ expectation of privacy by 

definition means more than a subjective expectation of 

not being discovered.”).
12

A.

The thrust of Stanley’s argument on appeal is that 

Erdely’s use of the MoocherHunter was an unlawful 

search under Kyllo. We disagree, and hold that Stanley’s 

expectation of privacy is not one that society is prepared 

to recognize as legitimate.9

In Kyllo, police officers suspected that the 

defendant was growing marijuana inside of his home. 

533 U.S. at 29. Without obtaining a warrant, these 

officers parked across the street and scanned the 

defendant’s home using a thermal imager. Id. at 29–30. 

This device revealed that certain portions of the home’s 

exterior were unusually warm, leading police to believe 

that the defendant was using high-powered halide lamps 

inside. Id. at 30. The Supreme Court held that this scan

was a search, and established a rule that “obtaining by 

sense-enhancing technology any information regarding 

the interior of the home that could not otherwise have 

been obtained without physical intrusion into a 

constitutionally protected area constitutes a search—at 

least where (as here) the technology in question is not in 

 

9

The Government argues that Stanley did not proffer 

any evidence of a subjective expectation of privacy. Because 

we find that any such expectation would not have been 

objectively justifiable, we need not reach the question of 

whether Stanley adequately demonstrated that he subjectively 

held it.
13

general public use.” Id. at 34 (internal quotation marks 

and citation omitted).

One could argue that this language, considered in 

the abstract, encompasses Erdely’s use of the 

MoocherHunter. The MoocherHunter, like the thermal 

imager in Kyllo, is surely “sense-enhancing technology,” 

as it detects radio waves which cannot be perceived by 

unaided human senses. Further, Erdely used this senseenhancing technology to obtain “information regarding 

the interior of [Stanley’s] home that could not otherwise 

have been obtained without physical intrusion”: the fact 

that a wireless card associated with particular Internet

activity was located there. Id. See also United States v. 

Karo, 468 U.S. 705, 714–18 (1984) (holding that the 

government’s use of a tracking device to discover that a 

particular barrel was located inside the defendant’s home 

was a search for purposes of the Fourth Amendment). 

Finally, the government does not contend that the 

MoocherHunter is technology that is “in general public 

use.” 

Critical to Kyllo’s holding, however, was the fact 

that the defendant sought to confine his activities to the 

interior of his home. He justifiably relied on the privacy 

protections of the home to shield these activities from 

public observation. See Kyllo, 533 U.S. at 34 

(characterizing the thermal imaging scan as a “search of 

the interior of [Kyllo’s] home[],” which it considered to 

be “the prototypical . . . area of protected privacy”). See 
14

also id. at 37 (“In the home, our cases show, all details 

are intimate details, because the entire area is held safe 

from prying government eyes.”) (emphasis in original).

Stanley can make no such claim.

Stanley made no effort to confine his conduct to 

the interior of his home. In fact, his conduct—sharing 

child pornography with other Internet users via a 

stranger’s Internet connection—was deliberately 

projected outside of his home, as it required interactions 

with persons and objects beyond the threshold of his 

residence. In effect, Stanley opened his window and 

extended an invisible, virtual arm across the street to the 

Neighbor’s router so that he could exploit his Internet

connection. In so doing, Stanley deliberately ventured 

beyond the privacy protections of the home, and thus, 

beyond the safe harbor provided by Kyllo. See United 

States v. Broadhurst, No. 3:11-cr-00121-MO-1, 2012 

WL 5985615, at *5 (D. Or. Nov. 28, 2012)

(distinguishing the use of a MoocherHunter-like device 

from the thermal scan in Kyllo because “in Kyllo, the heat 

signals were not being intentionally sent out into the 

world to connect publicly with others.”); United States v. 

Norris, No. 2:11-cr-00188-KJM, 2013 WL 4737197, at 

*7 (E.D. Cal. Sept. 3, 2013) (“In this case the agents used 

Moocherhunter to pick up signals the defendant was 

voluntarily transmitting to [his neighbor’s router], not 

information confined to the private area of defendant’s 

home.”).
15

Stanley cannot avail himself of the privacy 

protections of his home merely because he initiated his 

transmission from there. See Smith, 442 U.S. at 743

(“The fact that [Smith] dialed the number on his home 

phone rather than on some other phone could make no 

conceivable difference, nor could any subscriber 

rationally think that it would.”). Most importantly, while 

Stanley may have justifiably expected the path of his 

invisible radio waves to go undetected, society would not 

consider this expectation “legitimate” given the 

unauthorized nature of his transmission. Rakas, 439 U.S. 

at 143 n.12. 

As noted in Rakas, “[a] burglar plying his trade in 

a summer cabin during the off season may have a 

thoroughly justified subjective expectation of privacy, 

but it is not one which the law recognizes as 

‘legitimate.’” Id. The defendant’s presence in those 

circumstances “is wrongful; his expectation is not one 

that society is prepared to recognize as reasonable.” Id.

(internal quotation marks and citation omitted). 

Similarly, in United States v. Kennedy, 638 F.3d 159, 165 

(3d Cir. 2011), we held that an unauthorized driver in a 

rental car lacks a reasonable expectation of privacy in the 

vehicle in part because he “not only acts in contravention 

of the owner’s property rights, but also deceives the 

owner of the vehicle.” 
16

Here, the presence of Stanley’s unauthorized 

signal was itself “wrongful.” When Stanley deliberately 

connected to the Neighbor’s unsecured wireless network, 

he essentially hijacked the Neighbor’s router, forcing it to 

relay data to Comcast’s modem and back to his 

computer, all without either the Neighbor’s or Comcast’s

knowledge or consent. Stanley was, in effect, a virtual 

trespasser. As such, he can claim no “legitimate” 

expectation of privacy in the signal he used to effectuate 

this trespass—at least where, as here, the MoocherHunter 

revealed only the path of this signal and not its contents. 

 

The presence of Stanley’s signal was likely illegal. 

A large number of states, including Pennsylvania, have 

criminalized unauthorized access to a computer 

network.

10 A number of states have also passed statutes

penalizing theft of services,

11 which often explicitly 

 

10 See, e.g., Cal. Penal Code § 502; Colo. Rev. Stat. Ann.

§ 18-5.5-102; Del. Code Ann. tit. 11, § 932; Fla. Stat. Ann. § 

815.06; Ind. Code Ann. § 35-43-2-3; Iowa Code Ann. § 

716.6B; La. Rev. Stat. Ann. § 14:73.8; Mo. Ann. Stat. § 

569.099; N.H. Rev. Stat. Ann. § 638:17; N.J. Stat. Ann. § 

2C:20-25; Okla. Stat. Ann. tit. 21, § 1953; S.C. Code Ann. § 

16-16-20; 18 Pa. Cons. Stat. Ann § 7611; Tex. Penal Code 

Ann. § 33.02; Vt. Stat. Ann. tit. 13, § 4102; W. Va. Code 

Ann. § 61-3C-5.

11 See, e.g., Ala. Code § 13A-8-10; Ariz. Rev. Stat. Ann. 

§ 13-1802; Del. Code Ann. tit. 11, § 845; 720 ILCS 5/16-14; 

Ky. Rev. Stat. Ann. § 514.060; Mont. Code Ann. § 45-6-305; 
17

include telephone, cable, or computer services.12 We

need not decide here whether these statutes apply to

wireless mooching,13 but the dubious legality of Stanley’s 

conduct bolsters our conclusion that society would be 

unwilling to recognize his privacy interests as

“reasonable.” This is particularly so where the purpose 

 

N.H. Rev. Stat. Ann. § 637:8; N.J. Stat. Ann. § 2C:20-8; 18 

Pa. Cons. Stat. Ann. § 3926; Utah Code Ann. § 76-6-409.3; 

Vt. Stat. Ann. tit. 13, § 2582. 

12 See, e.g., Ariz. Rev. Stat. Ann. § 13-1801; Del. Code 

Ann. tit. 11, § 857; N.J. Stat. Ann. § 2C:20-8; Or. Rev. Stat. 

Ann. § 164.125; Wash. Rev. Code Ann. § 9A.56.010; 18 Pa. 

Cons. Stat. Ann. § 3926. See also Alaska Stat. Ann. § 

11.46.200 (“A person commits theft of services if . . . the 

person obtains the use of . . . a computer network . . . with 

reckless disregard that the use by that person is 

unauthorized.”); Iowa Code Ann. § 714.1 (“A person 

commits theft when the person . . . [k]nowingly and without 

authorization accesses . . . a . . . computer network . . . for the 

purpose of obtaining computer services.”).

13 Some commentators consider the legality of wireless 

mooching to be an open question. See, e.g., Grant J. Guillot, 

Trespassing Through CyberSpace; Should Wireless 

Piggybacking Constitute a Crime or Tort Under Louisiana 

Law?, 69 La. L. Rev. 389, 399 (2009); Benjamin D. Kern, 

Whacking, Joyriding and War-Driving: Roaming Use of WIFI and the Law, 21 Santa Clara Computer & High Tech. L.J. 

101, 145 (2004); Matthew Bierlein, Note, Policing the 

Wireless World: Access Liability in the Open Wi-Fi Era, 67 

Ohio St. L.J. 1123, 1165 (2006).
18

of Stanley’s unauthorized connection was to share child 

pornography.

14

To recognize Stanley’s expectation of privacy as 

“legitimate” would also reward him for establishing his 

Internet connection in such an unauthorized manner. As 

the District Court recognized, had Stanley shared child 

pornography using his own, legitimate Internet 

connection, Erdely could have obtained Stanley’s address 

from his Internet service provider—just as he obtained 

the Neighbor’s address from Comcast. See United States 

v. Christie, 624 F.3d 558, 573–74 (3d Cir. 2010) 

(“Federal courts have uniformly held that subscriber 

information provided to an internet provider is not 

protected by the Fourth Amendment’s privacy 

expectation.”) (internal quotation marks and citations 

omitted). Stanley cannot conceal his location by 

establishing an unauthorized connection and at the same 

time ask society to validate his expectation of privacy in 

the signal-strength information that police used to 

determine that location in a more roundabout manner. 

See Broadhurst, 2012 WL 5985615 at *5 (refusing to 

allow the defendant to “serendipitously receive Fourth 

Amendment protection because he hijacked another 

person’s Internet connection to share child pornography 

 

14 Cf. La. Rev. Stat. Ann. § 14:73.8 (penalizing 

“accessing . . . of any . . . computer network . . . for purposes 

of uploading, downloading, or selling of pornography 

involving juveniles”).
19

files”). 

Although the analogy is imperfect, we believe that 

the MoocherHunter is akin to a drug sniffing dog in that 

it was only able to detect a signal that was itself 

unauthorized and likely illegal. The use of a drug 

sniffing dog, which allows police to detect odors that 

they could not perceive with their human senses, is not a 

search under the Fourth Amendment because it 

“discloses only the presence or absence of narcotics, a 

contraband item.” United States v. Place, 462 U.S. 696, 

707 (1983). See also id. (“[A drug sniffing dog] does not 

expose noncontraband items that otherwise would remain 

hidden from public view, as does, for example, an 

officer’s rummaging through the contents of the 

luggage.”). In this way, “the manner in which 

information is obtained through this investigative 

technique is much less intrusive than a typical search.” 

Id. Thus, “[t]he legitimate expectation that information 

about perfectly lawful activity will remain private is 

categorically distinguishable from [a defendant’s] hopes 

or expectations concerning the nondetection of 

contraband.” Illinois v. Caballes, 543 U.S. 405, 410 

(2005). 

Here, the MoocherHunter detected only a signal 

that was itself unauthorized, and as we have 

characterized it, likely illegal. At the time Erdely used 

the MoocherHunter, Stanley was connecting to the 

Neighbor’s router without his knowledge or consent. 
20

Without that contemporaneous unauthorized connection, 

the MoocherHunter would have been unable to function. 

And the MoocherHunter revealed only the path of the 

signal establishing this connection. It revealed nothing 

about the content of the data carried by that signal. 

Accordingly, Stanley’s privacy expectations concerning 

the path of his unauthorized signal are “categorically 

distinguishable” from expectations he would have had 

concerning the path of a lawful, legitimate signal. 

Caballes, 543 U.S. at 410.

B.

While we conclude that Stanley lacked a 

reasonable expectation of privacy in the path of his 

unauthorized signal, we believe the able District Judge 

went too far when she held that “Stanley exposed his 

signal to a third party and assumed the risk that the signal 

would be revealed to the authorities.” J.A. 23. Other 

district courts have embraced this theory as well. See 

Norris, 2013 WL 4737197 at *7–8; Broadhurst, 2012 

WL 5985615 at *5. Because of that, we believe it 

appropriate to address why we consider this a flawed 

approach.15

 

15 Because we hold that Stanley lacked a reasonable 

expectation of privacy, Judge Shwartz finds it unnecessary to 

discuss the third-party doctrine and Smith v. Maryland. In 

addition, Judge Shwartz has a different view concerning the 

doctrine’s applicability to the facts of this case. From her 
21

In Smith, a robbery victim told police that she was 

receiving harassing phone calls from a man identifying 

himself as the robber. 442 U.S. at 737. Suspecting this 

man to be Michael Smith, police asked Smith’s telephone 

company to install a pen register that would record the 

phone numbers he dialed from his home phone. Id. 

When the register confirmed that Smith had dialed the 

victim’s number, police obtained a search warrant for his

home and discovered additional incriminating evidence. 

Id. After he was indicted, Smith moved to suppress this 

evidence on the basis that police officers conducted an 

unconstitutional warrantless search. Id. 

 

perspective, even though Stanley’s transmissions to the 

Neighbor’s router did not specifically disclose his location, he 

voluntarily disclosed information to surreptitiously obtain his 

neighbor’s internet service that his neighbor could use to find 

him. A cybertrespasser like Stanley assumes the risk that his 

neighbor (the trespassed upon party) would take steps to 

discover his whereabouts and share whatever clues he has 

with the police, including those that provide a link that leads 

to his location. Like a footprint, the information that Stanley 

conveyed to the neighbor’s router may not in and of itself 

disclose his location, but it did provide a lead and by leaving 

it behind, Stanley assumed the risk it would be pursued. 

Thus, to the extent it is necessary to discuss the third-party 

doctrine, Judge Shwartz would conclude that, on the facts of 

this case, it provides another ground on which to affirm the 

District Court’s ruling that the use of the MoocherHunter here 

did not violate the Fourth Amendment.
22

In upholding Smith’s conviction, the Supreme 

Court acknowledged that it “consistently has held that a 

person has no legitimate expectation of privacy in 

information he voluntarily turns over to third parties” 

because that person “assume[s] the risk” that this third 

party will convey this information to the police. Id. at 

743–44 (internal citations omitted). As an example, the 

Court cited its prior holding that “a bank depositor has no 

legitimate expectation of privacy in financial information 

voluntarily conveyed to banks and exposed to their 

employees in the ordinary course of business.” Id. at 744 

(internal quotation marks and citation omitted). The 

Court then explained that “[w]hen he used his phone, 

petitioner voluntarily conveyed numerical information to 

the telephone company and ‘exposed’ that information to 

its equipment in the ordinary course of business.” Id. at 

744. Accordingly, “petitioner assumed the risk that the 

company would reveal to police the numbers he dialed.” 

Id. 

In Stanley’s case, the District Court held that 

“[b]ased upon Smith’s rationale, . . . Stanley did not have 

a legitimate expectation of privacy in the wireless signal 

he caused to emanate from his computer to the 

Kowikowski wireless router.” J.A. 20. The District 

Court explained:

The information logged on that wireless 

router was accessible to [the Neighbor] and 
23

through his consent, to Erdely. This 

information showed the private IP address of 

Stanley’s computer. Stanley, therefore, 

could have no reasonable expectation of 

privacy in the signal he was sending to or 

receiving from [the Neighbor]’s wireless 

router in order to connect to the internet.

J.A. 21. Accordingly, the District Court held that 

“Stanley exposed his wireless signal to a third party and 

assumed the risk that the signal would be revealed to the 

authorities.” J.A. 23.

We regard the District Court’s reasoning as flawed 

because Stanley’s wireless signal was not itself 

“information” that could be “conveyed” to authorities. 

Smith, 442 U.S. at 744. Rather, his wireless signal was

composed of radio waves that were associated with a

plethora of information, some of which the Neighbor

could convey to authorities, but most of which he could 

not. Specifically, Stanley, through transmission of his

wireless signal, disclosed to the Neighbor his MAC 

address, his private IP address, and the fact that his 

wireless card was communicating with Stanley’s router at 

particular points in time. Stanley, therefore, assumed the 

risk that the Neighbor would convey this information to 

Erdely.

 
24

Erdely, however, did not simply take this 

information to a magistrate and obtain a search warrant. 

Rather, Erdely used this information to conduct an 

additional investigative step that revealed additional 

information. Specifically, Erdely entered Stanley’s MAC 

address into a sense-enhancing device, which he then 

used to obtain additional information about the strength 

of Stanley’s signal at different physical locations. It was 

this additional information that Erdely used to obtain a 

warrant for Stanley’s home. Yet Stanley did not “assume 

the risk” that the Neighbor would divulge this 

information because the Neighbor never possessed it. 

And if the Neighbor had possessed it, Erdely would not

have needed the MoocherHunter in the first place.16

Were we to hold that Stanley exposed his “signal” 

under Smith by transmitting it to a third-party router, we 

might open a veritable Pandora’s Box of Internet-related

 

16 The District Court also appears to have erroneously 

equated Stanley’s wireless signal with the private IP address 

assigned to that signal. See J.A. 21 (“An internet subscriber 

does not have a reasonable expectation of privacy in his IP 

address . . . , and likewise, a person connecting to another 

person’s wireless router does not have an expectation of 

privacy in that connection, i.e. the private IP address, when it 

is available to that third person and anyone with whom that 

person shares the information.”). Just as a home is more than 

the address assigned to it, a wireless signal, as discussed 

above, is more than just its private IP address.
25

privacy concerns. The Internet, by its very nature, 

requires all users to transmit their signals to third parties. 

Even a person who subscribes to a lawful, legitimate 

Internet connection necessarily transmits her signal to a 

modem and/or servers owned by third parties. This 

signal carries with it an abundance of detailed, private 

information about that user’s Internet activity. A holding

that an Internet user discloses her “signal” every time it is 

routed through third-party equipment could, without 

adequate qualification, unintentionally provide the 

government unfettered access to this mass of private 

information without requiring its agents to obtain a 

warrant. We doubt the wisdom of such a sweeping 

ruling, and in any event, find it unnecessary to embrace 

its reasoning. 

V.

We conclude that Stanley lacked a reasonable, 

legitimate expectation of privacy in the wireless signal. 

While Stanley is neither sheltered by Kyllo nor defeated

by Smith, the unauthorized nature of his connection to the 

Neighbor’s router eliminates the possibility that society 

would recognize his privacy expectations as legitimate. 

Accordingly, we will affirm the judgment of the District 

Court.