So, as an IT professional and general all-around nerdy d00d, I carry a lot of electronic equipment with me and I wanted to get some clarification on a topic I'd read about here and there but which I'd never seen become the focus of a discussion. I know that checked baggage, if locked, has to be done so with a TSA-approved lock. I don't pack valuables in my checked bags so I don't normally bother to lock it. However, I've seen many discussions mention locking carry-on bags with real, secure locks that TSA can't open to prevent theft at the checkpoint (e.g. when your groper is giving you a groping and your back is turned). I know common sense dictates to demand that your belongings be brought with to the groping grounds and kept within your direct line of sight at all times, and that's sound advice, but acknowledging that extenuating circumstances do...extenuate... What is the exact legality/permissibility of locking your carry-on bag shut with a non-TSA-approved and actually-really-truly-SECURE lock, thus forcing TSA to wait for your presence to open your bag? Any links to official information regarding this are, of course, most appreciated.