Our venerable Raid Leader has dictated that people must be Karazhan keyed in order to raid in there, even though the requirement has now been removed. His reasoning is that by doing the instances on the quest chain you might pick up some gear, get experience of instancing, and of course get access to the upgradeable ring for Violet Eye reputation.
So last night I was in the Shadow Labyrinth attempting to get my first key fragment. Which was very easy due to the instance group I was part of on my hunter clearing the whole place first. We were helping out a level 69 Resto Shaman in the guild to get some badly needed XP, so I went DPS with a little bit of crowd control. I was watching the resto shaman to pick up some tips; he had the Tremor Totem down for the mobs which feared and seemed to be using Wrath of Air, Strength of Earth and I think Healing Stream Totem.
So 1/4 of the Karazhan chain complete, no loot and no instance healing experience. If the key fragment containers were somehow tied to the players in the instance then this sort of thing would not be possible, much like how the Chess event in Karazhan was changed so only those who did Chess could loot the chest reward. I'm not complaining because it worked in my favour in this instance, but I know a lot of this sort of thing went on before the Karazhan attunement was optional, so it did trivialise the attunement process for alts quite a bit.
Anyway I have plans to heal a Sethekk Halls run tonight so hopefully some healing experience in a real (virtual) world setting will be forthcoming.