Accidental or not, any contact to the head of another player should ALWAYS garner a minimum of a 2 minute minor for roughing, no questions asked!!! 4 officials on the ice and no penalty call against 'Pool party' was completely irresponsible and borderline corruption IMHO.
In this example, Acciarri was injured and taken out of the game with an injury. A 5 minute major should have been assessed.
I really believe that if a Leaf had been the perp, a penalty would have been called!!!
As an example, we all saw the mugging of Jarnkrok just inside the Caness blueline, again with contact with his head and neck. No penalty called!!! He then proceeds to go to the net where he is pushed into the Canes goaltender. Only Jarnkrok is issued a penalty on the play. This is NO LONGER referee error, but clearly it is referee corruption in favor of an American based team.
JMHO.