Ahh, yeah I would say the alliance that queued up, got the queue pop (they then knew it was a horde premade on the other end, cause the queuetime was less than 5 minutes for them) and then dropped queue, waited a few seconds and requeued. - Are the ones who are the exploiters here. This is what ally premades do whenever horde tries to premade, they open a game, drop queue and requeue to get their pugs that they want to farm.
Find out who is the premaders on alliance doing this and punish them for their abuse.
For one I saw Jibbaj on his stream today, with 10 people divided in two groups of 5 queueing for Warsong, counting down when to click "join as group" loudly on their voice comm program. When only one group had the queue pop and not the other grp with the same BG number at the same time, they left queue and requeued until they would get the same game so that they were 100% going to premade vs pugs.
This kind of behaviour is wrong and can only be dealt with by removing the premade priority queue that's pretty much ruined Battleground PvP on this server.