So I'm taking a break from my present project by keeping current on jurisprudential developments, and in the Ninth Circuit's opinion in United States v. Gonzalez [8 page PDF], I read:
Gonzalez contends that a temporary zone of privacy was created when he was alone with Standifer. It is doubtless true that "the Fourth Amendment protects persons, not places." However, "the extent to which the Fourth Amendment protects people may depend upon where those people are." . . . Here, however, the defendant . . . chose to conduct his criminal activity in a public area.
Gonzalez would have us adopt a theory of the Fourth Amendment akin to J.K. Rowling's Invisibility Cloak, to create at will a shield impenetrable to law enforcement view even in the most public places. However, the fabric of the Fourth Amendment does not stretch that far. He did not have an expectation of privacy in the public mailroom that society would accept as reasonable.
It was . . . disconcerting.