Well as a gay man .. I can give you my impression of this.
First of all, if you stick a straight guy in a barracks full of women, while he may find some of them attractive, and may even indicate such to them, unless there is a mutual attraction, nothing is going to happen.
The same is true of gays .. I can be a locker room full of naked men, and maybe I find some of them attractive, but unless I know they are gay, and are also interested in me .. there isn't anything really gonna happen there.
As far as kids go, I would dare say that there is a plethera of sexual experimentation that is going on in the scouts and any other environment where you put a bunch of young hormonal boys together ... nothing wrong with that, and it doesn't make them gay. I think every one of my friends growing up explored things sexually with each other and myself .. none of them are gay. I am not gay because of those encounters.
So honestly, from the perspective of the kids, I don't think anything is going to change, and they certainly shouldn't treat them any differently than they would have normally... if it not uncomfortable for the adults, it won't be uncomfortable for the kids.
On that note, my biggest concern with all this, is that there is a huge difference between "tolerance" and "acceptance" .. Currently the BSA is tolerating gay youth and allowing them to stick around .. that doesn't mean that they are going to teach the rest of the kids to be accepting of the gays in their ranks, and I see a major upsurge of "sponsored bullying" that will occur within the BSA toward the gay scouts that are open about their sexuality. That will make me sad.