the RIRs can not decide who is an "important ISP" and who is a "less important ISP that should prevented from having their own networks" (by being forced to use upstream addresses from "important ISP" -
If the RIR have not to check small allocations anymore, they can chack if an ISP is big or not. Number of transit, peering, bandwidth, number of customer... define if an ISP is big or not, and then RIR can decide if it *need* to be independent An ISP with a single 34Mbps line, a single transit and no peering can renumber.
renumbering is fairly easy for end sites, but a PITA for an ISP plus all his customers).
When an ISP is small, renumbering is not a really big problem. DNS changes can be automated. Router configuration, if it was good made are not a problem either. Host configuration is not a problem at all in v6. -- Xavier Henner Responsable de l'exp�rimentation IPv6 Nerim -- Fournisseur d'acc�s � Internet URL: <http://www.nerim.net/>