While everyone waits at nearly all terminals/airports nationally, and even on approach roads to terminals, I have seen several cases of targeted enforcement. More specifically, one never knows when its not just the whistle and the hand wave that's received, but rather a ticket for illegal parking, stopping, or whatever the regulation is for the specific area in question.
Point is, one can usually get away with it. But much like speeding, do it enough or simply be the one in closest to the cop and it may cost way more than 1hr of parking.