Not being able to move is an indication of sleep paralysis. You were probably conscious of your physical self, but your brain had you paralyzed so you wouldn't act out your dreams with your physical body. As for looking for parked cars and whatnot, I don't want to definitively say that it would distinguish between an OBE/AP versus a LD, but if you end up with a number of conclusive results, it would probably give you some personal confidence in the difference. I know it would boost my confidence if I found out I was "guessing" correctly!