Who does source address validation? (was Re: what's that smell?)

  Yes, but if i continue in my ideal situation of people
(mostly) filter their bgp customers, so they won't announce the
1918 space, or similar. even the large peers filter out each other
so they don't pick up 1918 announcements. Plus people use Robs
"Secure IOS Template" to drop extraneous bgp announcements for
unregistered/unassigned space (from IANA).

What you're doing makes plenty of sense, we agree
on that. I just wanted to be sure folks understood
it doesn't validate "valid" sources.