YUCK! Why in the world would you WANT to stay in a WW parking lot unless you had too or just needed a little bit of sleep? A lot of the Wal-Marts around here aren't in the best neighborhoods so staying overnight in their parking lot would be a little scary.
To me, staying in a WW parking lot is not camping. Sorry if I offend anyone but sleeping in the parking lot is one thing and setting up "camp" is another....