etc, etc.PC §46.03. PLACES WEAPONS PROHIBITED. (a) A person commits
an offense if the person intentionally, knowingly, or recklessly possesses
or goes with a firearm, illegal knife, club, or prohibited weapon
listed in Section 46.05(a):
(1) on the physical premises of a school or educational institution,
any grounds or building on which an activity sponsored by a school or
educational institution is being conducted,
Doesn't matter if the building is posted or not.