Fixed more difficult for thieves?

Round my way the local chavs even ride their 20 year old Apollo mountain bikes badly, rediculously low gear, swerving all over the road. Once they've got your bike it doesn't matter if they ride it badly or push it. Unless someone's chasing them nobody is going to bat an eyelid at a kid with a bike, no matter how he's riding/pushing it.

But they can wheelie !