We are working on the 192.x.x.x swamp right now. Rough estimates (with much more accurate data @ NANOG)
60% - invalid or missing contact information
This is interesting. How about a policy that says if nobody can contact you and none of your addresses are reachable, then after some period, your addresses get recycled.
By addresses not being reachable, are you effectively saying that any enterprise that does not want to connect to the Internet must use RFC1597 address space? Anyone have an idea how much of the address space is used for registered addresses of organizations that do not connect to the Internet? This is not a trivial question, because I am aware, at least, of an assortment of military networks who have registered addresses, connect with other arbitrary military networks with their own registered addresses, and really need some assurance that these internetworks will have unique addresses. Internetworks != Internet, so valid assignments may not be Internet reachable.