In my opinion, if I sleep in my car without setting a tent, burning fire, using camping cars - is not camping but parking :P car is standing and if the driver is inside or if not - who cares ;) it is a great way to spend a night for free everywhere. I am using my car as a place of sleep many times during my photo trips. Accomodation in Norway is quite expensive and I love to be on place whole night - watching the night sky, sunset, changing weather, I can always shoot from car when its raining, listening to music, turn on heating when too cold... perfect mini-house for me.