He did once when some time ago the Bruins' Marc Savard challenged him, when after being at the bench, Crosby returned to the ice without his visor to answer the challenge, then Savard refused to fight.
I think Niskanen was more worried about getting punched in the nuts than actually landing punches.
ZOMG I Sid punching some one in nuts joke!!!!! OMG I'm can't pull myself off the ground from laughing!!!! Its just that its so original and new. Thats what makes its so great is its originality. With a doubt joke of the year from this clever, clever man.