Which is why a MIME to non-MIME gateway has to de-canonicalize it, just as
it has to decode *and* de-canonicalize qp or b64.
But an ascii to ebcdic gateway is not necessarily a MIME to non-MIME
gateway. It might instead be a MIME-aware gateway from an environment
capable of supporting binary c-t-e's, to one that is not capable of
supporting binary c-t-e's. In such a case the thing to do would be
to convert binary to base64.
The last thing I want is to create a state where a MIME mail reader doesn't
know what to do with BINARY, because it might have been translated from
ascii to ebcdic (or vice versa), or it might have been preserved. Having
deployed products that send text messages as BINARY, encourages that state,
and does not provide any better functionality than if the c-t-e label were
7bit or 8bit (as appropriate).
It is not correct to assume that BINARY is at least as safe as 7bit/8bit
for the transfer of text files with long lines.
Keith