Something I've noticed when joining BGs (AV excluded because I don't pay attention there as much), even as solo or with my friend. The leader often changes as more people join before the event starts.

I've been leader a number of times in my party with my friend, get into the BG and she's the leader, and as other people come in, the lead gets passed off.

So, part of the problem is that people may not realise that they're the leader (something that shouldn't be an issues I'd say level 40+). Or if they are the leader, may not even know how to move people around in raid groups (another thing I've noticed is very common).

I'd suggest maybe a macro asking whoever is leader to put all your toons in something like group 8. "I am a multiboxer and will you please put the following toons into group 8: Toon1, Toon2, Toon3, Toon4, Toon5."