Well, I was questing with my shaman and i was trying to complete this quest "What Book? I Don't See Any Book" So I was goin to do it when i saw 2 hordes starting the quest. I was mounted and waiting for them to finish but I lost connection so when I logged back on again I saw the question mark for completition.
I guess if you have the quest and if you want it done, just wait around to see if anyone its going to do it and get credit for your quest without even fighting.