»In which we hear a public service announcement, with guitar

Know your rights, thanks to the Flex Your Rights web site. All of which has reminded me of Cody's experience with the man and the Mint, and a subsequent, similar scene at One Bush; and of the misbegotten MTA photo ban (and ditto in San Francisco); these incidents spurred me to carry a cheat-sheet of First Amendment rights as they pertain to photography. The ACLU had something similar and more wallet-sized, but I no longer find it on their site.
The path to protecting ephemeral rights is not through eroding existing privileges. To wit:

He that would make his own liberty secure must guard even his enemy from oppression.
and
Those who expect to reap the blessings of freedom must undergo the fatigue of supporting it.

Mr Thos. Paine, Ladies and Gentlemen, Mr Thomas Paine.
Other rights that are inconveniently disappeareing include the right not be be sniffed by a machine while waiting in line. Airline Security a Waste of Cash reads the title of the Bruce Scheier editorial on airline security in Wired. Never mind that we can again take fingernail clippers on commercial flights: "These programs are based on the dangerous myth that terrorists match a particular profile and that we can somehow pick terrorists out of a crowd if we only can identify everyone. That's simply not true." John Gilmore's hearing before the Ninth Circuit Court takes place this week: he is suing the US Government for prohibiting anonymous interstate travel.