Lie.
Safety is compromised when visitors are NOT permitted to carry firearms or other weapons. Always. Weapon prohibitions are anti-safety.
Besides, their "ban" is meaningless since everyone intent on harm will ignore it, anyway.
And, they are worried about their "image"? Their anti-liberty bigotry harms their image in my eyes. Allowing people to keep their rights inviolate while in your presence isn't an image killer; it shows you to be adult and reasonable-- nothing could be better for your image.
As for patronage, do you really want to attract people who want everyone around them to be helpless? What sort of people might want that? Murderers, rapists, muggers, kidnappers, cops, cowards, and other scumwads, that's who.
I'm much more likely to go somewhere that doesn't ban weapons than I am to go places that do. I weigh the decision carefully when I go to a slaughter zone which bans weapons; trying to decide if the risk is worth it. Usually I decide it isn't.
If you ban guns, using "safety" as your justification, you are a liar and I won't trust you in other areas, either.
