Wrote about this above and I'm pretty sure all in Florida or at least those around WDW its not allowed. And I can certainly see why.
We pulled in to the Walmart near WDW one trip, needed supplies to rewire my trailer at 4am. Within minutes there was a security vehicle circling me to see what we were up to. They have signs posted No Overnight Stays.
Most Walmarts around Orlando do not allow overnight stays but there are lots of Walmarts in Florida that do.