This whole keeping your bags unlocked for the TSA is complete bullshit, as soon as the bags are away from their eyes, there are the masses of baggage handlers who you damn well know have their own little criminal operations going.
Again, it can be a pain in the ass, but if you are going to fly with checked baggage, buy and pack a small Smith & Wesson .38 and declare it when checking in. Let the TSA see it and let them lock your bag.
Fly with a
Pelican 1650 case, slap on one a couple
Titanium Series Master Locks, and stencil your name on the bag, I can promise you that the airline will never lose your bag. The Govt and the airlines can't afford to have news stories about missing bags containing handguns missing in their 'safe' airports.