As for etiquette, here's what I did at the Will Rogers show two weeks ago.
1. Unload carry gun in the car. Leave all ammo in the car. (Bring empty magazine if you like, but keep it in your pocket).
2. Re-conceal weapon in normal holster.
Upon entering the show, there's usually a police representative checking and zip-tieing weapons.
3. I approached the check station and politely told the officer "I have an UNLOADED carry gun that is concealed, I would like to unconceal it so you can check it and zip-tie it.
4. Officer said "ok" (didn't seem to care.... During the draw I made a small joke that I didn't want to leave the gun in the car in the parking lot, and I asked before unholstering because I didn't want to surprise him. He said "good idea, thanks")
5. I Unconcealed the weapon, pointed it in a (relatively) safe direction (ground), locked back the slide and handed the weapon to the officer, still pointed downward.
6. Officer checked the weapon, asked me if I was carrying any ammo or magazines (no), he zip-tied it and handed it back to me.
7. I put the weapon back in cc holster.
(the zip tie was rather small. It was pretty easy to reholster the weapon with the slide slightly open. YMMV
8. During the show, I wanted to test fit my gun into a holster. I asked the vendor if it would be ok, he said "sure". I calmly unholstered, making sure the zip-tie was easily visible to the vendor, tried the fit and returned the gun to my holster.
9. Nobody batted an eyelash. No shots were fired.
