New Krystal Commercial, Copyright Infringement?

While watching the game today, I saw a new Krystal commercial that caught my attention.  It was for the new Krystal with crunchy onions, and on the surface appeared like numerous other fast food commercials.  A girl stood behind the cash register, ready to help a line of waiting customers.  In the line stood Ronald McDonald.  At first, you get a glimpse of his hair, then his signature feet.  Ronald’s face is never actually shown, but everyone will immediately recognize who he is.  Is this copyright infringement?  Obviously, mentioning one’s competitor in an ad is perfectly fine, but showing their mascot?  The fact that Krystal didn’t show Ronald’s face leads me to believe that using Ronald would pose some sort of legal problem.  But we know who he is without his face?  Does that make a difference?