"If you had done any of those things, Gryffindor would have gained points on Halloween, and I might even have allowed you your weapons—or never discovered them at all. But you chose the most reckless, violent, and disrespectful course available to you. So the answer is "no', Potter. I will not make an exception to an eminently sensible school rule so you can stab at shadows. If you're worried about trouble, perhaps you should try staying out of it."