This is the "very thin line" of which you speak ...
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized. - U.S. Constitution: Fourth Amendment
by not standing up for the "“principle of the thing” and allowing the search because "they can keep you hanging around infinitum" ... is no different than the idiot students that said they would give up their right to vote for an Ipod...
you are simply willing to give up another "right" in favor of reward or convienience.
Funny how searches are only “unreasonable” when they snare the guilty. Refusing a search affords instantaneous probable cause for the warrant, provided the stop is legal. Airport searches are not unreasonable because of public safety issues; the same argument can be made for the detection of illegal weapons and contraband on our motorways. An innocent civilian has nothing to fear and his/her personal safety is enhanced by the process (which I don’t believe is as pandemic as the article implies). By the by, how is iPods for votes an apt comparison?