I had also emailed a CCW instructor and he claims that "There is no specific charge related to those signs". They can ask you to leave and if you refuse it's trespassing.
esullivan, i quick couple of rhetorical questions are in order for you to ponder...
why would you enter some place YOU have been shown, by signage, they do not wish you to enter?
why would YOU wish to endure the angry confrontation with those kind souls of the property telling you to leave or if the property folks decide they don’t wish the confrontation go immediately to the phone so the nice LE who respond can discuss your situation?
why would YOU bet you life that the phone call(s) to the nice LE were’t made by an anti who tell the dispatch you are waving the big bad firearm around in a threatening manner, or there has already been firearm discharge cuz they know they heard a couple of booms!!
(wait, are there multiple sirens i hear in the distance; now large numbers of running foot stomps; wait i can’t understand you- everyone is screaming at me at the same time; oh i get it, you want to see my holstered gun, let me show you its holstered.....kapow numerous times!!
While you didn’t get hit in the barrage, but a friend or loved one who was with you did!) far fetched, no!
so surely esullivan, these risks and judicial conflict are not worth you ignoring a 5x7 sign?