As someone who works at an Int'l airport (in New Orleans of all places) and is partly responsible for the security of it, I might be able to share some insight. I've noticed differences in response according to what organization the authority figure belongs to. For instance:
Whenever I'm on a perimeter inspection and run across a shutterbug taking pictures of the airplanes, I may talk to him and see what he's up to but that's where it stops. As long as they're not photographing the fence, or trying to determine weak points we generally don't have a problem. As a fellow plane nut, I happen to carry my Sony with me when I'm on patrol
Our airport police are pretty good as well; as long as the person does not present a threat they have no problem. Our airport police are Sherriff's Dept., and most of them should have the CIB for stuff that went down during and after Katrina. I can't speak for the NOPD and the incident with the handicapped man, but I remember going to sleep on unarmed SAR duty and hearing gunshots throughout the night. Most of these guys are decent, until someone is rude to them.
Finally there are the private security guards. These are the worst. The most dangerous thing in this city isn't a gangster with an AK-47, it's a fifth-grade dropout with a clipboard and a plastic badge. We had to put our foot down a while back because they insisted on searching the rescue trucks, which include a load of axes and cutting equipment to access trapped passengers.
All in all, the cops and airport personnel are mostly professionals. The rent-a-cops....not so much

.