Pretty positive we were 15 people within the same instance. And it was Deadmines. It was fixed rather recently after that I recall. But we were 15 roughly in the same instance known as Dead Mines. Hundred percent Positive. They weren't raids, but they were dungeons and there was those that collected everyone in Westfall for a zerg into Deadmines. I was one :P
I know it was fixed since I couldn't do it a month or two later. For funsies.