I'm sure there are logistical issues I'm missing here, but I think it's time that "no guns" sign no longer have "the force of law" any more than "no food/drink" signs do. Of course unlicensed carry (better known as unlawful possession of a concealed weapon) already has its own consequences and legal doctrine, and always has...
I think the technical point you may be missing is that trespass under 30.05 is a Class A misdemeanor if you are carrying a deadly weapon. Since violating 30.06 involves carrying a deadly weapon, it is the same penalty.