Atlantean, I hear you. It is most annoying. I don't have TSA locks, but in the past I have accompanied my luggage to the TSA scan, and verified that the locks have been put on and closed again by making the TSA guy show me. Of course, that doesn't particularly endear you to the TSA staff, but, in Catherine Tate's eternal words.... "Face? Bovvered?"
Recently on my flight out of TXL I had my bags opened. They were locked and all that, but imagine my surprise opening them and finding a letter from Flughäfen Berlin on top explaining that my bag of equipment required a secondary inspection (I suppose a bag containing lead glass items leaves big black marks on the secondary x-ray scans).
S.