A "no guns" sign is nothing but a filter.
It filters out the guns which might be used to defend you, while those which would be used to murder the innocent pass right by, utterly unaffected. It works the same everywhere, every time, without exception.
The same for "no guns" rules.
How anyone could ever believe this is a good thing is something I can't wrap my head around. It is a delusion too bizarre for words.