I remember when my high school was attempting to enforce an mandatory "tuck in your shirts" for all guys in the school. Not girls, just guys.
Everyone hated it, but they enforced it out of fear of someone bringing a gun to school, which happened before.
Well, a friend of mine walked into the principal's office one day, shirt tucked in, and talked to him about it for a while. Gun safety this, gun safety that. Well as my friend was leaving, he said, "Oh yeah, one more thing..." and then he untucked his shirt, and took out 4 pistol size water guns and sat them on his desk. He was suspended I believe. But even so. It was to prove a point. He walked right into the principal's office, with four guns...and no one ever knew until he pulled them out.