QuoteIn a seminal case (Katz v. United States in 1963) the US Supreme Court, over the strenuous objections of the US government, upheld the right of the user of a payphone to claim a right to privacy in the contents of those communications. The Court held that the Fourth Amendment right to be secure in your "persons, house, places and effects" against unreasonable searches and seizures protected people, not just places. Thus, to determine whether you had a right against unreasonable seizure -- a kind of privacy right -- the court adopted a two-pronged test: did you think what you were doing was private and is society willing to accept your belief as objectively reasonable? The method you use to communicate can effect both your subjective expectation of privacy and society's willingness to consider that expectation as "reasonable." Shouting a "private" conversation into a megaphone at Times Square would neither be subjectively nor objectively reasonable, if you wanted the conversation to be confidential. "Broadcasting" the conversation over the radio is likewise unreasonable.