public market vs personal residence
According to local law enforcement, not even a stop sign placed on private property (ie: as found in a mall parking lot) can be enforced by police. I understand there are certain laws which protect a person in their own home. However, your analogy doesn't make sense. I have never gone through a parking lot and placed an advertisement on thousands of random vehicles inviting people to my house. I'm pretty sure that places of public business (which advertize to or "invite" the generl public), whether they be on public or private property, do not have the same legal discrimination rights as private citizens do regarding their place of residence. I understand that they can post any signs they wish. However, the ability to legally enforce them, and cause me the expense of having my vehicle towed, is a different matter. Just because it is private property doesn't mean they can just do whatever they will with my personal vehicle. Since you want to compare this public market to a personal residence, by your logic I should be able to post a "no trespassing" sign on my door and then shoot whomever I should decide is uninvited.