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Page Number: 102

4 

CARPENTER v. UNITED STATES 

GORSUCH, J., dissenting 

able expectation of privacy in it.  Smith, supra, at 744.  But 
assumption  of  risk  doctrine  developed  in  tort  law.    It 
generally  applies  when  “by  contract  or  otherwise  [one] 
expressly  agrees  to  accept  a  risk  of  harm”  or  impliedly 
does  so  by  “manifest[ing]  his  willingness  to  accept”  that 
risk  and  thereby  “take[s]  his  chances  as  to  harm  which 
may  result  from  it.”  Restatement  (Second)  of  Torts 
§§496B,  496C(1),  and  Comment  b  (1965);  see  also  1  D.
Dobbs, P. Hayden, & E. Bublick, Law of Torts §§235–236,
pp. 841–850 (2d ed. 2017).  That rationale has little play in 
this context.  Suppose I entrust a friend with a letter and 
he  promises  to  keep  it  secret  until  he  delivers  it  to  an 
intended  recipient.  In  what  sense  have  I  agreed  to  bear
the risk that he will turn around, break his promise, and 
spill  its  contents  to  someone  else?    More  confusing  still,
what  have  I  done  to  “manifest  my  willingness  to  accept” 
the  risk  that  the  government  will  pry  the  document  from 
my friend and read it without his consent? 

One  possible  answer  concerns  knowledge.    I  know  that 
my  friend  might  break  his  promise,  or  that  the  govern-
ment might have some reason to search the papers in his 
possession.    But  knowing  about  a  risk  doesn’t  mean  you 
assume responsibility for it.  Whenever you walk down the
sidewalk  you  know  a  car  may  negligently  or  recklessly
veer off and hit you, but that hardly means you accept the
consequences  and  absolve  the  driver  of  any  damage  he
may  do  to  you.    Epstein,  Privacy  and  the  Third  Hand:
Lessons  From  the  Common  Law  of  Reasonable  Expecta-
tions,  24  Berkeley  Tech.  L. J.  1199,  1204  (2009);  see  W.
Keeton, D. Dobbs, R. Keeton, & D. Owen, Prosser & Keeton 
on Law of Torts 490 (5th ed. 1984).

Some  have  suggested  the  third  party  doctrine  is  better
understood  to  rest  on  consent  than  assumption  of  risk.
“So long as a person knows that they are disclosing infor-
mation to a third party,” the argument goes, “their choice
to do so is voluntary and the consent valid.”  Kerr, supra,