"

The third-party doctrine is a United States legal doctrine that holds that people who voluntarily give information to third parties, such as banks and phone companies, generally have "no reasonable expectation of privacy" in that information. This precedent, established in Supreme Court cases in the 1970s, allows the U.S. government to obtain information from third parties without a legal warrant and without otherwise complying with the Fourth Amendment prohibition against search and seizure without probable cause and a judicial search warrant. "

https://en.wikipedia.org/wiki/Third-party_doctrine