Originally Posted by
chaud
Let me give you a little history here.
1. Long long ago, in a WoW many patches away, they removed the Join as Group button, but left in the command to do it. An addon was created that used this code, people QQed, and Blizzard disabled the Join as Group Command as well.
2. Today, addons like Preform AV Enabler queue your entire raid for AV at nearly the same time, after everyone has opened the window. The leader can see how many people get the same game, and drop queue if it is not acceptable. There is no function in the addon that allows you to join as a group, it simply removes human error from the process.