Most
people would agree with the assertion that if you want to keep something private,
then you just shouldn’t tell anyone! And that is just the rule that the Supreme
Court developed in Katz v. United States when it contemplated matters
that are not considered “private,” in regards to the Fourth Amendment. The
Court stated that “what a person knowingly exposes to the public . . . . is not
a subject of Fourth Amendment protection.” A little over a decade later, the
Court expanded this notion in Smith v. Maryland to create the third-party doctrine,
which states that “a person has no legitimate expectation of privacy in
information he voluntarily turns over to third parties.” The idea behind the
doctrine is that citizens should take steps to protect their privacy or to
preserve their secrets; and if a citizen puts their personal information out to
another party (usually a business with the third-party doctrine), then that
information is obviously not private—and more importantly, it is not protected
under the Fourth Amendment from government intrusion.
