I don't know how I feel about that sort of thing (I do really
). I know it's a bit of an outlaw passtime, but taking the keys with you on exit, or otherwise screwing with the aircraft, just seems a little bit too stupid to me. Fortunately I haven't had to contend with that.
I did hear of a similar situation where revenge was exacted by packing a brick into the guy's main. I suppose that's equally stupid eally.