Interesting dilemma. Firstly, since most of these events are held on city or government owned property, they are posted improperly to begin with.
TPC 30.06
(e) It is an exception to the application of this section that the property
on which the license holder carries a handgun is owned or leased
by a governmental entity and is not a premises or other place on which
the license holder is prohibited from carrying the handgun under
Section 46.03 or 46.035.
Second, that raises another question. According to TPC 46.0035
(a) A license holder commits an offense if the license holder carries a handgun on or about the license holder's person under the authority of Subchapter H, Chapter 411, Government Code, and intentionally fails to conceal the handgun.
We've gone around and around on this forum before about disarming in public. Most seem to agree it violates 46.035
However, at many of the gun shows, there are police officers doing the diarming.
GC §411.207. AUTHORITY OF PEACE OFFICER TO DISARM.
(a) A peace officer who is acting in the lawful discharge of the
officer's official duties may disarm a license holder at any time the
officer reasonably believes it is necessary for the protection of the
license holder, officer, or another individual.
It could also be argued that asking a CHL holder to disarm at a gun show held on public property (IE, city owned convention center, like the Brown Center here in Houston) is not lawful, since the convention centers are illegally posted.
The whole thing is a tangled web of wrong. IMHO, the cities should be smacked across the face for allowing gun shows to improperly post 30.06 signs. And the chain of stupid hurts. You're telling me to disarm, when I could still walk right in, snip off the stupid zip tie, buy magazines and ammo, and have a functioning weapon within minutes?
Personally, I think I'm done giving my money to gun shows until they remove the 30.06 signs. I can walk right into any gun shop, walmart, or sporting goods store and buy most of the same junk they sell, not disarm, not deal with the crowds, parking, and save $8 in admission.