It seems the OP question is less about Wallyworld (which has been discussed ad nauseum) and more about simply boondocking. Doesn't matter whether it is WM or other parking lot, or a forest service/COE campground with no hookups. If you don't want to boondock, just don't do it. Each family will have to decide for themselves.
We boondock frequently. And catching 6-8 hours sleep in some parking lot is common. Gets us more time at our destination. We've never used WM, but truck stops, rest stops, mall parking lots, and even mountain road pull-offs have all "hosted" us for some zzzzz's.