Personally, I have never cared for people putting flyers in my car at car shows. They should just hand them out. If we happen to step away for a bit, we can come back and have paper in the seat of the car. While I don't think that it is cool, I haven't made an issue of it. At least not like a phord guy that was parked a car or two away from us at a Saturday car show. He went off on some guy dropping a show flyer in his car and it almost got out of hand. Quite a show at the show.
I think the Phord guy got so pissed because the extra weight of that flyer would slow his car way down.