It never occured to me to think parking flashy cars up front had anything to do with tipping. I'm a crummy tipper (well maybe average) and yet when I have the MBZ or have ahd former BMWs parked and they often end up out front. I've always thought it was more a matter of parking a flashy car such as a Ferrari or a Boxster out front of a restaurant or hotel gives a sort of free advertising to the place, telling all who pass by that this is a hot place to go.