No Right Turn On Red

So we were coming home tonight and stopped at a red light. In front of us was a police car. Next thing hubby said was, "No right turn on red." Yep, sure enough that police car turned right at the red light with that "no right turn on red" sign clearly posted on the pole. I'm not even sure he used a turn signal either. Why is it okay for them to do that? Just doesn't seem quite right but what can you really do? Nothing I suppose but complain about it in a blog huh?