As you know, the wait for a damage dealer can be long, like 1 hour.
So I get joined to the LFR sylvanas but I could not get in because of the ongoing encounter. 10 seconds later the few people alive in that group kill Sylvanas and I can get in but of course because I did not participated I got no loot, I just lost 1 hour of waiting in the queue only to end up on the back of the queue again
Please Blizzard either let people teleport during ongoing encounters in LFR or do not join them during encounters… do not waste peoples time by resetting their queue.