Now regarding the damage that might happen to a car... many years back now, I had my car sticking half-way out the garage (backed in) on one side, while I was up on a ladder on the other side of the garage... I leaned against the ladder and hit the remote in my pocket closing the door on the hood of my car. This was an old, poorly maintained 80's era opener. It took a second to realize what was happening, and once I figured it out, there was no way to get off the ladder or dig through my pockets in time. I watched in horror as the door came down on my hood and pushed my Suburban hard enough to see the front end dip a bit. However, it did finally reverse, and there wasn't a mark on the vehicle.