Ignorant and infrequent flyer here. I'm having trouble visualizing the risk. If I'm the bad guy, do I grab someone's bag, turn, and leave? Do I grab someone's bag, search it, remove a perceived valuable item, stow it in my bag, return the original bag, and put my bag on the conveyor? I understand the TSA employees probably do not watch the passengers fiddling with their bags carefully, but it seems like either scenario has a high chance of getting caught and a low probability of reward. What am I missing? I would think it would be much more important to be waiting for the bag when it comes out. Thanks for insight.