G.A. Heath wrote:1. 30.06/30.07 signs on public property not listed in penal code sections 46.03 and 46.035 is not enforceable.
2. Government code 411.209 opens governments up to fines for wrongful exclusions.
3. Texas AG opinion KP-0108 concludes that an entity that leases government property at arms length may post notice, but it is unenforceable.
4. Gun shows most likely do NOT meet the "at arms length" provision due to the short term nature of their leasing the facilities.
It is completely legal to carry past these signs. You might want to avoid OC given the possibility of harassment. Then again, you may want to avoid the show entirely since they are willing to (most likely) break the law to infringe on your civil rights.