Did you know that the TSA approved locks are single-use, disposable? It must be.
I checked a bag to SFO couple weeks ago. I spent 20 bucks for 2 of those disposable locks. I also only packed clothes in the checked bag. No metal, no wires, no batteries. The clothes I put in the checked bag had no metal studs. There should be no reason for the TSA to open my bag but I used a TSA approved lock, just in case.
After I retrieved my bag, I didn't look at it until I got to the hotel. When I started to unpack, I noticed the lock was gone. There was also cut marks on the zipper.
The bag was checked in Seattle. My conclusion.....Seattle TSA