If being IDed a the airport strikes you as a gross violation of privacy, you must lead a pretty good life the rest of the time.
Here's a fellow who took matters into his own hands, resisting the airport Gestapo by refusing to show ID to anyone but the personnel of his airline. Wow. What a freedom fighter.
Reason, from whence I stole this link, takes a more positive view of the passenger's antics.
UPDATE: There are more where that man came from, reports the Times.