I think this is one of the tackiest forms of advertising. Plus you chance of reaching a prospective client are very low. You have know way of knowing who the car your putting it on belongs to . It could be a high school kid. a person in an apartment or rental. Someone who's yard looks like a war zone. someone from out of town. etc... I would never do this. I do use door fliers but I knock on the door and hand it to them and introduce myself if they are home. If they aren't home then I attach it to the door knob /handle.