Actually no, there is a rather significant chance for nobody in a 12-man group to pull a raid item. 11.2% chance. And in that same 12-man party, there is only a little over 60% chance that 2 or more raid items will drop. Someone calculated it all out in the announcement thread, it's very interesting to see:
Edit: The math is sort of accurate. It overestimates the chances of getting loot in some places.