IMHO it's not just the tip, it's the car. If you pull up in a Taurus and toss the guy a $50 he ain't gonna put it out front. He'll keep it VERY close by and get it on demand, but won't put it out front. Any car with a LITTLE panache (Mercedes C-class, Infiniti G35) can be put up front if it's well detailed. Even in New York (when I've driven) a $20, a wink, and a "Hey, would you mind making a bit of room for her up front?" will do it.
[This message has been edited by kanebear (edited 08-20-2002).]