I just thought that I would post this link to some tests of motorcycle chains being cropped.
[ame="http://uk.youtube.com/watch?v=VC3hFr8p2ck"]YouTube - Various Sold Secure and Thatcham chains chopped.[/ame]
I realise that these men where using a lot of force on the locks with full size bolt croppers but I think it goes to show just how vulnerable locks can be if the thief has a few moments alone with a locked bike. There again if you saw two guys with uniforms and hi-viz jackets cropping a lock and loading a bike into a van would you ask them what they where doing?
BTW, I don’t use any lock on my folder, I take it with me