First, citing its third-party exposure cases, the Supreme Court stated that “the Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities.” Id. at 443 (citing United States v. White, 401 U.S. 745, 752, 91 S. Ct. 1122, 28 L. Ed. 2d 453 (1971); Hoffa v. United States, 385 U.S. 293, 302, 87 S. Ct. 408, 17 L. Ed. 2d 374 (1966); Lopez v. United States, 373 U.S. 427, 83 S. Ct. 1381, 10 L. Ed. 2d 462 (1963)). Second, the Supreme Court observed that bank records “[were] not the respondent’s ‘private papers'” but were instead “the business records of the banks.”
In fact, the Supreme Court has made clear that the use of undercover agents – even when the agent wears a wire – does not constitute a “search” under the Fourth Amendment. Lopez v. United States, 373 U.S. 427 (1963); On Lee v. United States, 343 U.S. 747 (1952); Hoffa v. United States, 385 U.S. 293 (1966); and United States v. White, 401 U.S. 745 (1971). As the Court has reasoned, betrayal by ones associates is always a risk, so there is no expectation of privacy in those interactions if they involve an undercover agent.