A woman is attacked in a Wal Mart parking lot, and an employee of the store tried to help her. He was fired, because the retail store has a policy against it.Businesses do not care about you. To them, you are a walking wallet with a potential lawsuit attached, and they will do whatever the law will allow to escape that liability.
This is why I do not follow “no guns” signs. The law says that they can avoid the liability of a lawsuit if they prohibit weapons, even if prohibiting weapons means that the criminals are free to kill everyone in the store. It also says they are liable if there is not a policy, and someone with a weapon injures someone. No brainer: they prohibit weapons.
The law also says that they are liable if one of their employees uses force to injure someone, even if that someone is a criminal. So the result here is that you, as a customer, are on your own.
However, at least in Florida, the law also says that I am free to ignore your silly sign, and that is exactly what I do.