This is my first post here, but I have to comment as things are relative. Compared to the camping stories I have encountered recently, a car parked on your spot is nothing.
Last outing I was on, I was parked at a CG where my neighbor's spot is in the center of a long row of occupied pads. So, people would cut through inches from his fifth-wheel's slide in order to have a shortcut rather than drive to the end of the row. The CG owner saw the tire tracks, but dismissed them as them being there previously. Even when I showed video footage from my phone, the CG management said that it was a false accusation, and threatened both of us with being thrown out.
Outing before that, I was dry camping at a SP. Around 11:00 at night, I hear my generator turn on, and find my neighbor had multiple plugs into it. My generator was running the neighbor's outdoor entertainment center so his rug rats can play XBox. I stopped that party, and the neighbor tried to get in my face, claiming he was entitled to run my generator for his kid's "medical reasons". The fact my camping buddy who was with me has a CHP badge ended the situation by encouraging the neighbor to take their leave, which they did.