Apologies for awaking a dead post.
Isn't there a proper fix for the Alt-F4 abuse by now? Not only in battlegrounds I have this issue, also in dungeons. After a disconnection/'hic up' I am kicked out of the group and left the dungeon. It is frustrating to ask the group members to invite me back and then run the whole instance to the point i dropped out. This for me ruins the group activities.