Comment by ThePhysicist

Slightly off topic, but I think bike thieves are becoming more and more professional recently. Here in Berlin many now use small cordless screwdrivers with a custom gearing mechanism that operates a bolt-cutter. With that they can even cut through thick steel-bar type bike locks in a few seconds, without making any noise. I saw that in a police report lately but I can't find a link with a photo of the device now, unfortunately. It's really quite ingenious from a technical point of view. It seems the only way to protect against theft is to ride an old bicycle.