apparently only hipsters use U-locks
i think it's linked with the amount of bike messenger-rage-leadingtowindowsmashingwithaulock
stories that seem to get offered up on the internet
they are fairly prevalent
that said, just because you hit some guy with a bike lock, it doesn't make you a hipster.
and that said, bike messengers are fuck heads who think its ok to leave a 2mm gap when they fly past you at 20 kph with not so much as a warning bell.