Well, I agree that in of itself it's not a big deal, but a dress code is a dress code, you can alter it, preferably by vote rather than fiat, but it's not what the violation is, it's that someone is violating it. It would seem pretty silly to throw a fit over someone wearing a t-shirt under their suit jacket when the event stipulates ties too, but we are talking about teenagers, just on general principle you want to keep the rules enforced, whatever they are. Forgetting the whole gay thing, for the moment assume someone was demanding the right to attend wearing cowboy boots and hat, you slap them down, this is a school we're talking about after all, kids shouldn't be in the habit of expecting to get their way.