Well, this can be argued the otherway around as well. We know that ISPs filter out previously unused space, and that they are not very active in updating those filters when IANA starts allocating out of new blocks. Having all in well-known block would limit that.
...wouldn't we/you/they/all have to do some filtering the "other way 'round" if all of those prefixes are contained in _one_ superblock to guard against someone/something announcing (and potentially black- holeing(sp?)) a route for that /32?
Eh, I would assume there is no /32 to announce and that more specifics will always win.
- - kurtis -
In a perfect world - yes. But "per default" when you announce something in v6-world, you are "supposed" to announce a /32 (or maybe a /35) _and_ filter anything that is longer than that. I really don't see any benefit from adding complexity again, other than clinging to the well-worn conservatiopn goal from IPv4. Wilfried.