Yeah, the mirror trick is a good way to get the point across with no permanent damage or major inconvenience.

Here in the south we have those big duelly pick-up trucks (with two tires on each side in the rear) and hips wider than a GT3 RSR, plus tow hooks which can be dangerous when parking bumper to bumper! There's guys like me that park the car really far out to avoid dings, then guys like those who park far out thinking it's easier than navigating the crowded part of the parking lot. For some reason no matter how far out I go, I almost always come out to an SUV or pick-up right next to me!!!

 

Those duelly owners are car guys who park their track car haulers next to your car to protect it from other less considerate drivers.