Right, but emphasize that the granularity is a signing domain -- it is
not and cannot be a way to attribute mail to individual people.
Unless you have reason to believe that the signer is taking steps to ensure
that the sender information is accurate. I'd say that a DKIM signature from
a reputable service provider would quite likely increase the *chance* that
the sender information is accurate. Of course, you can't be certain (with
any technology), because any account might be compromised by phishing.
Why isn't a signed 822.From sufficiently accurate sender information
from a provider who cares?
NOTE WELL: This list operates according to