An interesting question
There was some argument regarding whether a private entity which forbade firearms in an area, or in parked cars, might assume some liability to a person who became a victim of crime because they could not defend themselves.
So many people are risk averse. They try to avoid all the obvious risks, sometimes by making other, worse risks, more likely. I am convinced that the “Unarmed Victims Here” signs are put up by people who think they are limiting their liability. I think that as soon as someone sues because he could not defend himself, these signs will come down. The insurance companies will insist on it.