Weird copyright idea of mine: copyright registrations lapse, and must be paid for regularly, but the copyright itself continues. You have to have a registration to be able to demand statutory damages and can only demand for the period of the registration. So, if it lapses, you can't demand anything. No copyright zombies, because if you cared enough, you'd have made sure the registration was up to date. But it still falls close enough to treaty requirements to not get thrown out.