It's probably the dual effect of random queue changes and the /report change.

Bots are scripted these days to follow people. So when a player sees several toons packed on top of one another they are /reporting. So beware of this.

We've gone round and round on this on the WoW forums (I go by Orcmasha on there). People are now realizing what bots like honorbuddy do. They don't stand at the GY jumping up and down anymore. They actually follow and engage so long as one human is present and making decisions on objectives.

That of course means you guys will get caught up in it as multiboxing looks very much like a cluster of honor buddy bots. Could be too that you were mass reported before and it's just the /report feature change that is doing it. Either way I'd steer clear of BGs until they fix it.