as of yesterday I was doing what I described in my post... so I don't know what you're referring to.
I was doing it in SoO, blackrock foundry, and hellfire citadel and managed to get a piece of cloth on a warrior. So It seems that I actually CAN.
edit:
just cause I could..
I hopped on a DK and ran SoO heroic again and got a cloth piece from immersius. which is impossible on personal loot