We spent a few nights at various Walmarts before we came across the first one that did not permit over night stays in their parking lot. It caught me so far off guard that after we got home I decided to call Walmart's corporate office and ask what their position was about over night stays in their parking lots. What I found out was that it is left totally up to each store manager, and their decisions are usually based on space and the affect it has on traffic. They told me to make sure I talked to the manager, and not an employee.
A few weeks later we were traveling and needed a place to spend the night, so I pulled into a Walmart, and went in to ask if it was alright to spend the night in their parking lot. An employee told me no it was not alright, so I ask for the manager, he told me that the manager would tell me that same thing. I still ask to speak to the manager, after a few minutes he came and talked to me. I ask about spending the night in the parking lot, and he said that it was fine as long as we stayed as far away from the store as possible. That is when I realized the corporate office knew what they were talking about when they told me to speak to the manager.
This is not a typical article for me, but I thought it was worth sharing, especially if it will help another Wallmart camper find a place to spend the night. There are a few Walmarts that have signs posted that over night stays are not permitted, that makes it pretty clear. As long as there are no signs, and there are others set up and camping, I don't ask, but if I am the only one in the parking lot, I always ask the manager, and so far neither one has told me no.