Assuming the thief has time to work with, no lock can resist methods such as being frozen and smashed with a sledgehammer, or cut with a torch.
Or melted with thermite, or cut through with a pressurized air tank hooked to a cut off tool with a diamond wheel. Why, I've even heard of prisoners in prison using floss dipped in glue & sand to cut through bars & escape. <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />
Someone can even see your key from 200 feet away & copy it:
Keys Can be Copied From Afar, Jacobs School Computer Scientists Show
