Here in Florida, wearing a skian dubh onto school property, regardless of good intentions, would be a felony, and those that enforce such laws are not particularly amenable to reason and have absolutely no sense of humor. I wouldn't be at all surprised to learn that Wisconsin has similar laws on their books, enforced with the same degree of vigor. With the level of violence and resultant siege mentality in American schools these days, I personally wouldn't dream of bringing a weapon of any kind, no matter how innocuous; my life's already quite complicated enough.