How exactly will a lock that TSA personnel can open at will stop or deter a TSA employed thief?
The TSA lock flags red whenever it is opened by any means other than the combination, which only the traveler should have. I don't know if it would deter a thief. I wasn't addressing the efficacy of locks, but rather your comment, "but now the security procedures preclude the use of locks" which, given my experience, I believe to not be the case.