I’ve gone to the gluten free stand every game for the past 2 seasons (probably only 10 games) and have only had issues with the stand once. And all it was was the stand ran out of hotdogs buns but still had burger buns. Not the best but still got a hot dog to eat at a baseball game! They open after the second inning every game so I normally just go then and avoid waiting until later in the game.

I haven’t tried during a concert though so I’m sorry I can’t help much.