filtering long prefixes

Yes, Geert Jan, but if you look at the list I prepared,
you'll note that the only chunks of old style Bs that are
18-bits long all come from one home-AS and most are in a
pair of old-style class Bs which easily could be aggregated
into a single /15 with the loss of some routing specificity
(which is lost anyway when that provider's internal metrics
don't propagate to its external peers).

The remainder of the 'chunks' of old style Bs are
all longer than 18 bits, and most are /24s or /26s,
and I see none at all that appear difficult to aggregate,
or which look like anything other than leaks due to

If you get to the point where someone needs to have a /18
in the old-style class B space and it can't be aggregated,
we can return to this.