Once, I inadvertently carried a folding, Uncle Henry Bearpaw lockback into a courthouse in Brooklyn. As I did not wish to be harassed, I attempted to check it rather than have it id'd as a weapon. [I had modified the blade to bring it under 3", with a tanto tip.] It was confiscated anyway as I had lubed the mechanism so well that it could be opened one handed when the lock was free. They called it a gravity knife and confiscated it on those terms. I believe one of the court officers wanted it for his own.