Rented a car once and my co-workers and I decided to stuff a box of crackers in the air vents, needless to say you can figure out the rest of the story, it was a hot day too...
Hey if you think rental cars get abused you don't want to know what happens to them at the dealership before they are sold as new cars to consumers...... All of the above stated are done and much worst. We just always make sure the car stays under 30 miles on the odometer. Most dealerships have dent repair and paint touch up people on site. For these exact reasons.