..., but instead of a blackhole, it would be more like a realtime
pushback list (RPL), which has some nice properties of punishing known
abusers, but not causing complete collateral damage to innocent parties.
the definitions of your words "known", "abusers", and "innocent" are highly
subjective and are known to vary considerably from one recipient to the next.
y'all have got to stop trying to save smtp, and just agree to move on. smtp
was an ivory tower thing and it isn't working well down in the fields.