With apologies to another entry that I can't seem to find.
The national organizations' decision to "punt" gay scout/ adult leader membership to individual units, if it actually happens, is fantastic news. To understand this, you have to understand how scouting is organized. While the national and regional organizations get the press, the heart of scouting is entirely local. Each unit (troop, crew or pack depending on boy scouts, venturing or cub scouts) is organized by a "chartering organization". The chartering organization selects and vouches for the adult leaders and sets the unit policies - within national guidelines. The units promise to follow scout rules on things like youth protection, advancement, health and safety, and unit structure (a troop is made of patrols,...) While there are national standards and policies for the adults, ultimately it is the responsibility of the local community - which knows the adults to vouch for them. (there is a background check that national performs, but that won't catch everything). While units can make mistakes, this is actually a good idea because who knows the volunteer better than his local community?
I have known adult homosexuals who would make great scout leaders, and known adult heterosexual adult leaders who should never be near scouts (not for sex, but because they were bullies and lead by intimidation rather than letting the scouts lead themselves).
If you are a scout or adult leader in good standing with a unit, then you are a scout or adult leader in the BSA. So if the palaeolithic knuckle dragging unit troop 666, doesn't admit gays, and the enlightened unit troop 777 does (I don't think are real troop numbers and my apologies if they're your unit), then the knuckle dragger's have to accept the presence of members of troop 777 at district, council, and national events - whether they like it or not.
Venturing (high school and college age) already works something like this. Some units are co-ed, some are all male and some are all female. The choice is up to the chartering organization. But if you are a venturer, then you're a venturer and if you attend a multi-crew district event, it does not matter if some other unit would not accept you for being a gender they don't want.
Their could be some conflict at Eagle scout boards of review (the final step in advancement) where at least one member of the board of review comes from a unit other than the scout's. It would be an automatic accepted appeal if a scout in good standing was rejected for a personal quirk that was accepted by his unit and followed national guidelines. If national says a unit can accept gay scouts then rejecting a gay scout, otherwise in good standing, for being gay and unacceptable to your unit, would mean that scout would be able to appeal and revoke your decision. This is just like rejecting a scout for being black, having blond hair, or being a different faith - all of which would be immediately overturned.
While it sounds weasily, letting individual chartering organizations to set their own policies avoids a lot of problems. Let the homophobes march to their own drummer, off into the sunset.