Inappropriate Fantasy

OK, time to expose my darker side.

I've occasional thought about renting a car for a week , putting it up on jack stand, pulling the wheels off, and setting the cruise control speed to - oh say - 140mph. After a week the odometer would have logged a good 20k plus miles. I figure it would get really good mileage given the lack of wind or rolling resistance. You have to figure that the clerk would be surprised when the car was returned.