Just bringing my two cents to the topic now that I have something to tell you
I was running my daily HM and the Foundry popped out also the group seemed to be nicely geared so in we go. At the first conversation running in the background I asked for the Jugg tank if he could guard my BH marauder and I got the guard although the around BH geared sorc healer started to whine loundly and continously he would absolutely need the guard. The tank left the guard on me still and in we went but the healer let the tank to die against the first groups of thrash there and went on aggroing the groups first and did not care to heal the tank. The tank asked the healer to play nicely but he refused which made the tank to leave before the first boss.
After that we had a verbal "fight" with the healer who was really acting and behaving like a douche. He insisted "he is so damn awesome with his heals that he always needs guard because he creates so much aggro...And his guild's tanks always guard on him!" I really had to laugh at him and I let him know how hilarious he sounded. When GF popped us a new tank the healer got his guard then.
The "fun" did not stop there though! From the first boss to HK he was not healing me at all because "my attitude was rubbish"
Well I just killed normals on those groups then and let the others aggro and kill the silvers and golds. I also let them know during the convo with HK-47 that I will only kill adds during the fight as I won't get healed. Suddenly the mood for the healer changed and he stated "oh okey then, get over it and lets just do this"
Well we finished Foundry rather nicely but my ignore-list still got one new name onto it...