Just got out of AB that Horde was winning, then all of a sudden a lot of our players started dc-ing and lagging. I've seen this happen before on other servers when alliance was losing, certain players or multiple players dc-ing and getting lags. Yes I'm implying exactly that what you're thinking, some rotten alliance individuals can't lose like real men.
The alliance wasn't affected by this lag and they took all bases during it, resulting in their undeserved win.
I've also made a ticket with screenshots of the players who were there. I dare say the one(s) responsible for this lameness is/are listed there.
Additionally a suggestion on how to find the one repsonsible. It may be that the responsible party hadn't won it's first daily BG yet, so if you have a way of checking the logs of people who had played and lost until that Arathi Basin.. that may narrow down the search (servertime included on the screens)