Just wanting to chime in with a thought, it may not be a simple setting but the ability to balance things out will be there from the get go. Guilds could deploy strike teams to their respective borderlands to keep their own BL buff to themselves, therefore all teams will have +50, noone has +150, things remain balanced.
Call it a convoluted and bad solution if you will, but if you ask me the meta PvP between the teams trying to support the GvG and any WvW players trying to ruin their fun will add to the show. Say what you will about how you shouldn’t have to do that to have your fun, but that’s what you get when you try to bootstrap honorable, organised battles into a game mode that is by its very nature and intent chaotic and unpredictable.
This is a battle you folks are probably better off fighting with the virtual sword in game than the virtual pen in the forums. At the very least, you’ll save yourselves a lot of time and effort till Anet actually gets around to implementing a game mode for you guys to do this in officially.
tl;dr: Can’t win what you want with reason? Take it by force.
