I wouldn't suggest using a super ACME turbo charged leaf blower, but I've never had any problems. I have one of the cheapest ones I could find for the cars. I think like $20something at Walmart. I don't use the big daddy one we use for the yard work on it though. Plus, I'm doing it inside a clean garage so not much stuff flying around, either.
Try it sometime, so you neighbors can laugh at you, lol
Oh, just realized, you're talking about actually hitting the car with the blower. Yeah, that would suck. Again, why I bought the lightest cheapest one I could find. I've seen some pros actually pad the end with MF so if they hit the car it won't damage the car.