Other members have said this better than I. “No Firearms” signs are for open carry issues. Try this at home: Create a simple sign that disallows open carry, just to keep customers at ease, but allows concealed carry customers. I couldn’t succeed.
I f I had a place of business, other than a bar, I would somehow encourage as many lawfully carrying citizens as I could muster. As long as they were concealed and not a topic for open discussion.