So, I'm getting the impression that it's a great idea...</internet sarcasm>

But seriously, I can understand being afraid of psychos and whatnot. And even the extremely rare "my glove got caught in the trunk, and I lost my hand, bike, wife, dog..." Are these the only two arguments against it? I'm only touching the vehicle with my fingertips, and I'm not smudging up windows or anything. I'm not saying that this is a great idea, but I thought that if there was such a resoundingly negative response, there'd be a few more reasons.

So, any reasons besides psychos and getting dragged?

EDIT: Just saw the video. That guy was an idiot. You DON'T lean on a car that is still moving. And don't lean on the hood. And don't tap your fingers, that's just asking for trouble.