According the Huntington Handbook of Humorous Hijinks: "If one is to say "knock knock" and the opposing person(s) does not respond with "who's there?" the person who is telling the joke, under the international laws of warfare section 3A subsection 5, has the right to immediately explode the person whenever he or she pleases, within a 10 to 15 second time frame after which the person(s) has not responded with "Who's there?""