There is another fix for it. If neither provider allowed spoofing, then
the individual couldn't send spoofed packets out one way and allow the
syn/ack back via the other. Of course, there are better reasons for
spoof protection ingress/egress than a little port 25 traffic.
This is what our, atleast, abuse team calls 'fantasy mail'. There is a fix
for it, port 25 in and out filtering for radius customers. The 'problem'
as I understand it, is that the change would be a contract change so it
has to wait for expiration of said contract to be enforced... :( Its a
sucky world sometimes. Perhaps Paul complained to
ATT/<other-unnamed-provider> with logs and such? :)