If you bumped your car into another car, but nobody saw you do it, would you leave your name and phone number?

I've done this once. I hit another parked car without saying or leaving anything. It was a truck with a chrome bumper versus my yellow Mazda hatchback. My yellow Mazda had a dent in it's plastic bumper, the truck a spot of yellow on it's metal .... what on earth would have done any good if I had left a contact?