Why do signs say "no concealable weapons allowed"?

I work in a state facility in the US, and there are signs at the doors which say "No Concealable Weapons Allowed" with a picture of a handgun with the red slash through it. Recently the signs had been replaced, the former wording was "concealed". My thought is, "so it is OK to walk in with a bazooka, because it is not concealABLE"? (Or concealED, with the old signs) Why don't they just say "No Weapons" which should be the point? What distinction am I missing here?

Solution 1:

Presumably, if the sign had said "no concealed weapons allowed" and you took the prohibition literally, you might conclude that you could enter with either a bazooka or a handgun readily visible in your hand(s).

The point of the distinction here, I suspect, is that—what with the emergence of "open carry" laws in various state and municipal jurisdictions of the United States—the facility where you work wanted to emphasize that carrying a handgun or other "concealable" weapon inside the facility is prohibited, whether it's visible or not. I admit that the bazooka loophole looms rather large, but I wouldn't recommend testing it: Even a howitzer is concealable if you have a big enough tarp.