Texas law already makes it a crime to do what they're doing but so far nobody has the stones to make an arrest.
§ 39.03. (a) A public servant acting under color of his office or employment commits an offense if he:
(1) intentionally subjects another to mistreatment or to arrest, detention, search, seizure, dispossession, assessment, or lien that he knows is unlawful;
(2) intentionally denies or impedes another in the exercise or enjoyment of any right, privilege, power, or immunity, knowing his conduct is unlawful;
The law is crystal clear, in black and white, in plain English, that 30.06 and 30.07 don't apply where "the property on which the license holder carries a handgun is owned or leased by a governmental entity" unless the property is off limits under § 46 like a courtroom or a secured area of an airport.
More laws are not the answer. Law Enforcement needs to enforce existing laws or they're part of the problem.
ICYMI IANAL TINLA OK?
Also, there's not much point in adding open carry when enforcement is nearly nonexistant for improperly posted 30.06 signs. Now, if the law was changed to allow each affected LTC to individually bring suit against offenders in small claims court, for civil rights violations, I bet the signs would come down a lot quicker. Can you imagine the effect of even a few hundred Harris County residents each bringing a separate $1000 suit against a local offender? 