E.g prevously announced address-blocks that has disappeared from the global routing-table for more than X months should go back to the RIR-pool (X<=6).
In RFC 2050 section 3 a) the organization has no intention of connecting to the Internet-either now or in the future-but it still requires a globally unique IP address. The organization should consider using reserved addresses from RFC1918. If it is determined this is not possible, they can be issued unique (if not Internet routable) IP addresses. Seems to me that the Internet routing table contents past and present are irrelevant. Note also that the so-called Internet routing table contents vary depending on where you look at it. In any case, at the ARIN meeting in LA there will be an Open Policy Hour for people to suggest things that the RIRs should do. More info here: http://www.arin.net/ARIN-XVI/agenda/tuesday.html#policy --Michael Dillon