Well I spent a lot more than $1600 at Walmart last year, and I didn't sleep in the parking lot a single night! Moreover, I cannot imagine what's going on in the head of somebody who thinks it's okay to sleep in their parking lot and yet doesn't consider Walmart their "preferred store for shopping". Just your preferred store for sleeping? What about panhandling?
If Walmart wants you people sleeping in their parking lot--and you're not too proud to do so--that's their business. But to sneer at the idea of shopping there without sleeping there is just bizarre.