Tanks and healers would just ask players to votekick them if they’re in the “wrong” instance or after they’re done with the bosses and requeue fast.
But they did, the first iterations did not include a debuff. Leaving and holding groups were rampant. Even in the latest response here they added additional penalty requirements:
Current suggestions are to add all loot randomly to the last boss of the instance or a Warbound penalty instead to prevent leavers from requeueing on other toons.