At some point, businesses just get tired of getting beat up by crime, litter and the rest of the things that go along with this sort of situation.
I would bet, this law was not enacted, because they got tired of retired folks spending money in their town, and parking at the local Walmart. So I would think it was probably directed at another group of folks that are camping at walmart
Having some experience with this sort of situation (because of where my office bldg. is), I would say although I want to be compassionate, I will say as the years went on, my compassion tended to fade.
So I can understand Medford's decision.