Cedar Rapids, IA Rwy 27 Pre 9/11 you could stand within the approach lights (outside of the airport fence) all day. After 9/11 I was told to leave by a police officer because I cannot loiter.
Cedar Rapids, IA Rwy 9 Post 9/11: I was told that I cannot park on the side of the road and had to leave.
Denver Intl: My friend and I took lots of pictures a few months ago and the police drove right by.
Most absurd: Portland Intl You will see on your 10-9 Jepp chart the note that says “Twy T between the North Ramp and the General Aviation Ramp closed to through traffic. I heard they built a fence to keep the GA people/planes away from the Airliners. The ironic thing is that if for some reason a GA plane or person wants to breech the airline security, all they have to do is taxi on A4-A-A5 and they effectively bypassed the fence. Of course they could take the grass between the taxiways if they were in a hurry.
The most Ironic: I recently few out of a feeder airport in Denver with a friend in his plane. He instructed me to go through X FBO’s doors and meet him on the ramp. I proceeded to walk through the FBO, note the huge “NO UNAUTHORIZED ACCESS PAST THIS POINT” sign, and as I am still walking, say “hi” to the people at the desk and proceed out to the ramp through that restricted access point.