Some of his buddies put a cardboard cut-out of a pistol wrapped in aluminum foil in his bag without him knowing it.
There was this one a-hole in an advanced weapons school. The night before leaving the school, got drunk and put a training grenade in his bag (we were all packed and ready to fly out the following morning). This was in '85, right after the Achille Lauro hijacking, so metal detectors were newly installed at many airports. He-he...his bag set off a buzzer, bag opened, a-hole Sheldon got his arse jumped, and we laughed and laughed and laughed...
(that was 23 years ago, and I'm still smiling...that dude was such an a-hole)