Someone should inform the owner of this car, if his car is hit and damaged by another driver, the other driver is not responsible. In fact, the owner of this car can be held liable for damages. There is a reason why it is illegal to park this close to a stop sign.

Oh and if you really want to get the point across, call the police and tell them that this car has been parked out here with the boot for about a week and that no one has moved the car. You don't know who it belongs to, etc. Give them the location and the plate #. Then maybe the police will tow the car to impound. Maybe that will teach the owner to follow the law.