It's a joke. You can't control knives. They can be pounded out of or made out of nearly any piece of thin metal and every kitchen has at least a dozen.
True, just like an axe or a chain saw, the whole thing is a joke- but its disgusting an off duty solidier butchered in the the street
That's not a joke. The thought that knives could be confiscated or registered is a joke. It' not possible. Probably not even under Hitler.