Well frankly I think it's a waste of time to ask for permission in most cases.
If there are already RV's in the lot that look as if they are going to stay, and this should be clear by the time of day or their slides out, then you can assume it is just fine...just be nice and park on the outskirts of the lot as many have said.
The problem with asking is this: many employees just don't know what the policy is at that particular store. Second. There may not be an ACTUAL POLICY, it may be just a casual thing at that store.
While some stores have rules and some have posted them on signs others do not. Much depends on the store, it's location, it's level of business, the size of it's lot etc.
If I do ask, which I rarely do because it is obvious that they either allow it or not, I ask the young guy that collects the shopping carts, he is in the parking lot more than anyone and sees it all.
Don;t worry too much. It's an easy thing and Wal Mart benefits from our patronage.
