I know there are enough riders mounting car tires on their motorcycles to warrant discussion, but as a topic of personal interest it ranks pretty low on my totem pole. For starters, it's not something that has a huge impact on the general population. Loud pipes, for example, attract a lot of unwarranted attention, a fat tire, not so much, so as far as social impact goes the issue is a non-starter. Secondly, I've known guys that have been running car tires on their bikes since the early 60's. Since none of them are running amok leaving havoc and mayhem in their wake, I'd have to think the practice is fairly innocuous, although one of them has been known to say nasty things about his ex-wife.