Why does Principal Owens summon Ross to his office?

Mr. Ross is called to the principal’s office by Principal Owens because he is very happy and curious about The Wave—at least at first. When Mr. Ross explains that The Wave is meant to teach students what life was like in Nazi Germany, Principal Owens worries that it is too “open ended” (78) and that it might go too far. However, Mr. Ross thinks that he can put a stop to The Wave whenever he wants because he is the leader. He reassures Principal Owens that The Wave won’t become a problem.