I've often been puzzled by the ham-fisted approach that the TSA uses for checked baggage search. In places like Frankfurt, the German
Bundesgrenzschutz also searches baggage on a very regular basis-- but they are smart enough to know that almost all baggage has locks that are so generic that I've been told they have a big keyring with all of the keys-- "oh, the Samsonite there is key #43." This allows them to open, search, close and lock the traveller's baggage without having to resort to the less technically-advanced TSA method-- a #4 crowbar and Baggage Gorilla Badge #383931. Thankfully, they are not issued sidearms otherwise I fear they may try to shoot-open the locks.
When I travel through the USA (it is mostly only a transit stop for me) I don't like leaving my bags unlocked because my destination normally is Latin America, an area where there is a risk of baggage being pilfered before arriving on the claim carousel, which is in itself a security risk.