Roy Badami>
In such an organization, publishing MARID records will require a
change in organizational policy, rather than just changes in
departmental policies. It just requires one department head to argue
that his users don't have time to deal with this to block adoption
across the entire organization. Per-user policy allows piecemeal
adoption on a per-department basis, and is therefore more likely to
happen.
It's not clear that this is true. Administration of the domain
"organization.tld" must be centralised. I guess subdomains might be
delegated. There seems to be no insurmountable difficulty in making sure
that all legitimate outbound MTA in the organisation are included in the
MARID record, for the top level domain. Perhaps you could try to explain
the problem a bit more clearly?