How about just keeping a running list of everyone who has been in group since a quest was started, and as chests are opened, roll loot for only those people.
Wouldn't this prevent the "Muck Dead. 2 Slots for free chance at muckbane" type issues, while also not killing loot for the dude that recalled out at the moment a chest was opened?
Couldn't this be applied as a better solution to some of the raid loot issues?