WalMart Camping

This is not how you overnight at WalMart! This is at the Fort Stockton, Texas store, they have chairs and BBQ out!

That's a good example of why it is prohibited in some places.

most do not allow park lot camping due to regulations from the locals. They fear loss of $$ due to the free camping. We have seen this type of activity here in our local wm for days at a time.
We generally do not park in these areas, have actually done it 1 time in montana prior to entering ND, it was late and raining, so stayed in big truck stop/casino along with 5-6 others. All they said was to stay out of way of the big rigs.