perhaps, but an agent should not be performing that part of the MUA's
function for messages accepted via the SUBMISSION protocol.
I never said it was or should do so. But what people actually run on
various
ports is, in the final analysis, their own affair. We can only state
whether or
not something is standards compliant.
we can do a bit better than that - we can also state that we design and
test things to interoperate when they comply with the standards, and
not (in general) under other conditions. if someone writes or
configures a protocol engine to deviate from the standards, he does so
at the risk of degrading interoperability, and impairing the network
for his own users and possibly for others. very few users have the
background and analysis skills to understand the implications of
deviating from the standards.