Something I try to remember is cell phones almost all have cameras now. Also in some cases I'd be inclined to let the air out of the tire(s) of the other car to make sure it stayed put. But that's risky, they may be so mad they take it out on my car or me. We often leave one of us with the car when it's a quick stop. We have also chose to not go somewhere because of the parking situation. Sorry for the troubles.