IMO, the ultimate aim (even if this is not practical) is to deliver to
each recipient the same version of the Fax as they would have received IF
they were the only addressee while at the same time generating only the
minimum number of copies to allow multi-
That is a worthy and reasonable use for this capability. And, of course
yes, it motivated creating this option.
However that level of "perfection" is not required. There is nothing wrong
with a service model that is satisfied with sending the least common
denominator.
The choice is the sender's.
as long as the sender gets to specify the conditions under which the
conversion is done, that seems just fine - it is no different than
allowing the the sender to personally look at a set of potential
recipients' capabilities and decide what the minimum requirements
for reception (and therefore the LCD format) should be.
however the current proposal doesn't really give the sender a way
to specify that threshhold - unless, perhaps, the negotiation/conversion
is performed by an MTA that is under control of the sender (in which
case the threshold could be specified by explicit configuration)
and that MTA has the abliity to speak SMTP directly with MTAs that
know the recipients' capabilities.
in other words, enabling the sender to make the choice is not
compatible with the vast majority of the deployed email
infrastructure (even assuming that those MTAs are extended to
support this extension)
Keith