>> And, before you pop off any more about closing open relays...I'm talking about instances where sysadmins verified that no open relays are/were involved.
It is practically impossible to verify that no open relays were involved...not to mention unheard of. Spammers ALWAYS use open relays because they don't want to get caught. If you have actually received spam that was not routed through an open relay then you must have received spam from the dumbest, poorest spammer on the Internet.