One lesson that I learned was to ALWAYS have copies of both TSA's and the airline's policies on hand. Like many of you, I did lots of research before traveling with my firearms. That was one of the things stressed, as well as knowing what generally to expect. When I was checking in at HNL the first time, the agent said I needed TSA locks. Well, no, and here's the TSA rules and YOUR airline. She went to check with a supervisor, who confirmed, and was all good. The only "trick" was to wait in the baggage check in area to allow the gun case to pass TSA, otherwise I would have to come back out. Most other airports that I've been to have a separate TSA area when you hand off the gun cases to them and they inspect it in front of you. I've never had them ask me to open up my gun case.
On one trip, the shooting instructor and I were invited on a flight seeing tour by another shooter in the class. He was a local and set us up with this sweet flightseeing tour around Denali. It was AWESOME! Anyways, I carpooled to the tour with the instructor and I caught a ride with him to the airport after. He does training all over the world and he often gets to train with explosives and stuff. TSA gave him a SUPER hard time about this gun case swab. I thought they were going to have him completely empty his gun case.
Somewhat back on topic, I've seen some pretty flimsy gun cases when picking up my gun case. I've seem some with as little as one lock near the middle of the case. I wouldn't think it would pass the "no pry" rule, but I guess it flew.

I didn't want to take a chance and ended up getting a Pelican. However, those cases are damn expensive and that was also when I had more disposable income.