% As John Klensin pointed out on this same list several weeks ago
% (and I'm sure he said it better than I will), the decision to
% use ambiguous local addressing in IPv4 (i.e. RFC 1918 addresses)
% was partially motivated by the desire to conserve IPv4 address
% space. In IPv6, we don't have an address space shortage, so there
% is no reason to introduce architectural complexity to conserve
% address space.
%
% Margaret
"dont' have an address space shortage..." - Margaret
-YET-
IPv4 didn't have one either, in its early days.
--bill
Opinions expressed may not even be mine by the time you read them, and
certainly don't reflect those of any other entity (legal or otherwise).