I had a lock cut off once...but they were nice enough to tape the pieces to the TSA card before they stuck the card in my bag.

I had a second checked bag on that trip which had the same type of lock, but it wasn't cut off - I'm guessing the first bag was opened because it contained, among other things, safety boots and a small belt pouch w/a flashlight and a multi-tool while the other bag just had boring old clothes and toiletries.