AirBnb vs CAN-SPAM act. You make the call
ref: http://www.justice.gov/criminal/cybercrime/ccmanual/03ccma.html

E. CAN-SPAM Act: 18 U.S.C. § 1037

The CAN-SPAM Act of 2003, Pub. L. No. 108-187, 117 Stat. 2699 (2003), which became effective on January 1, 2004, provides a means for prosecuting those responsible for sending large amounts of unsolicited commercial email (a.k.a. "spam"). Although civil and regulatory provisions are the primary mechanism by which the CAN-SPAM Act's provisions are enforced, it also created several new criminal offenses at 18 U.S.C. § 1037. These offenses are intended to address more egregious violations of the CAN-SPAM Act, particularly where the perpetrator has taken significant steps to hide his or her identity, or the source of the spam, from recipients, ISPs, or law enforcement agencies.

In addition to section 1037, the CAN-SPAM Act contains another criminal provision, codified at 15 U.S.C. § 7704(d), which prohibits sending sexually explicit email that does not contain a label or marking designating it as sexually explicit. A knowing violation of this section is punishable by a fine, imprisonment for not more than five years, or both. For questions regarding the application of § 7704(d), please contact the Child Exploitation and Obscenity Section of the Criminal Division of the Department of Justice at (202) 514-5780.

Title 18, United States Code, Section 1037(a) provides:
Whoever, in or affecting interstate or foreign commerce, knowingly—
(1) accesses a protected computer without authorization, and intentionally initiates the transmission of multiple commercial electronic mail messages from or through such computer,
(2) uses a protected computer to relay or retransmit multiple commercial electronic mail messages, with the intent to deceive or mislead recipients, or any Internet access service, as to the origin of such messages,
(3) materially falsifies header information in multiple commercial electronic mail messages and intentionally initiates the transmission of such messages,
(4) registers, using information that materially falsifies the identity of the actual registrant, for five or more electronic mail accounts or online user accounts or two or more domain names, and intentionally initiates the transmission of multiple commercial electronic mail messages from any combination of such accounts or domain names, or
(5) falsely represents oneself to be the registrant or the legitimate successor in interest to the registrant of 5 or more Internet Protocol addresses, and intentionally initiates the transmission of multiple commercial electronic mail messages from such addresses, or conspires to do so, shall be punished as provided in subsection (b).
1. Commercial Electronic Mail Messages

Section 1037 only criminalizes conduct involving "commercial electronic mail messages":
(A) In general. The term "commercial electronic mail message" means any electronic mail message the primary purpose of which is the commercial advertisement or promotion of a commercial product or service (including content on an Internet website operated for a commercial purpose).

(B) Transactional or relationship messages. The term "commercial electronic mail message" does not include a transactional or relationship message.

15 U.S.C. § 7702(2).
2. Materially

Sections 1037(a)(3) and (a)(4) require proof that certain information was "materially" falsified:
For purposes of paragraphs (3) and (4) of subsection (a), header information or registration information is materially falsified if it is altered or concealed in a manner that would impair the ability of a recipient of the message, an Internet access service processing the message on behalf of a recipient, a person alleging a violation of this section, or a law enforcement agency to identify, locate, or respond to a person who initiated the electronic mail message or to investigate the alleged violation.

18 U.S.C. § 1037(d)(2).
3. Multiple

Section 1037 only criminalizes conduct involving "multiple" commercial email messages:

The term "multiple" means more than 100 electronic mail messages during a 24-hour period, more than 1,000 electronic mail messages during a 30-day period, or more than 10,000 electronic mail messages during a one-year period.

18 U.S.C. § 1037(d)(3).
4. Penalties

A violation of section 1037 is a felony punishable by a fine, imprisonment for not more than five years, or both, if:
(A) committed in furtherance of any felony under the laws of the U.S. or of any State; or

(B) the defendant has previously been convicted under § 1037, § 1030, or the law of any State for conduct involving the transmission of spam or unauthorized access to a computer system.

18 U.S.C. § 1037(b)(1).

A violation of section 1037 is a felony punishable by a fine, imprisonment for not more than three years, or both, if:

committed in violation of § 1037(a)(1)

committed in violation of § 1037(a)(4), and it involved 20 or more falsely registered email accounts, or 10 or more falsely registered domains

the volume of email messages transmitted in furtherance of the offense exceeded 2,500 during any 24-hour period, 25,000 during any 30-day period, or 250,000 during any one-year period

the offense caused an aggregate loss of $5,000 or more to one or more persons during any one-year period

any individual committing the offense obtained anything of value aggregating $5,000 or more during any one-year period; or

the defendant undertook the offense with three or more persons and occupied an organizer or leadership position

18 U.S.C. § 1037(b)(2)(A)-(F).

All other violations of section 1037 are misdemeanors, punishable by a fine, imprisonment for not more than one year, or both. 18 U.S.C. § 1037(b)(3).

Section 1037 also contains specific provisions relating to forfeiture. 18 U.S.C. § 1037(c). For more information about forfeitures, please contact the Asset Forfeiture and Money Laundering Section of the Criminal Division of the Department of Justice at (202) 514-1263.