My car is now highly decorated. One night on my way home from DC, a trucker was honking like crazy, waving and giving me the thumbs up.
My car is parked for hours on end in DC and I've never had a problem. Once in Richmond someone pulled my GITMO and Support the Troops magnets off my trunk. My friend found them in the trash can around the corner, so I put them back on before I moved the car. ;*)
We were in the parking lot of WalMart when we were commenting on he various stickers along those same lines, when the owners walked up. They seemed pleasantly surprised we were in agreement!