Haha. Yeah, I've yet to figure out how I feel about rejecting people. A tricky road I haven't yet been down. Part of my issue is, I have no place to explain why I'm rejecting or to make explicit how I think the branch should take shape—which could provide some clue as to why somebody's proposal for their own inclusion doesn't meet my desires.
The underlying question, for me, is this: In starting a branch, am I an editor, a moderator, a contributor, a catalyst? I don't have a clear sense of the model, probably to @branch's credit: Flexibility, here, will probably suit the platform best. But I definitely find myself wanting advice or wanting to see a kind of set of common practices evolve.