When I see a slide extended at our local Walmart parking lot, that tells me the RVer is staying for awhile, and not just shopping. Having a dog pen and camp chairs out tell me the same thing.
The way I look at it is that RVers are slowly taking more and more advantage of the gracious opportunity and as we are seeing, overnight stay will eventually be eliminated. The key, as I see it, is that everybody has a different idea of where that line is on being acceptable to do in the parking lot. You can read some of the above posts and see that people draw a line, but that line is individual, and once the homeless RVer starts staying in the parking lot all the time, management will be forced to stop it. Just like all rules, the few ruin it for the rest of us. IMHO