Oh no, I do not like it when any parent plays favorites!! Punish my child if it was only my kid doing wrong, but don't act like yours is an angel if he was participating too!
Your comment reminds me of working in a daycare center. I was in the classroom with the owner's son in it. He would come in eating popsicles or lollipops while the rest of the kids just stared at him, practically drooling. And if you tried to tell the owner about his misconduct, she would just chuckle like it was nothing. It was infuriating!!