Paper Tiger
... in which case do not put anything of value in them (a wise precaution anyway IMO).
Uummm, where do you start considering your clothing as having a 'value'? Is it when they take your M&S underwear, or when they take your Saville Row suit? If I place a swatch of 24 CDs in my hold case - so that my hand luggage will not exceed permitted weight - is that placing something of value in the case?
Those, such as the TSA, that have the legal right to open suitcases cannot guarantee that every other person in the chain (at least two airports and maybe more if through checked) are going to be well behaved. To then require you to leave the case unlocked ...?
When I lived in Munich, they x-rayed the bag at check-in. In fact, you had the bag and hand luggage x-rayed BEFORE you were allowed to queue for check-in. That was 1998~2000!!! Sensible and practical, the TSA should learn from them.