Thanks for your input Chollie, but I think you're wrong.

Don't confuse TSA with Travel Sentry - the commercial organisation that licenses the "red diamond" idea. TSA don't actually "approve" any locks. They can't. The best you can say about the Travel Sentry/Safe Skies systems is that their locks are "TSA recognised". It's a loose arrangement relying on the adequate training and IQ of TSA inspectors. Better to give them a problem that is easier to solve. The ClipLok even has a picture of a pair of bolt-cutters at the place where it should be clipped!

Incidentally, if they do cut it off, all you have to do is replace the shackle when you get it back. You won't need to go through the hassle of trying to claim a replacement lock. It's a no-brainer really.

I've also been able to open one of the Travel Sentry locks with a paper clip!