Perhaps this will alleviate some confusion.
* All this draft does is define an MX that says "you can't send mail
here." It's intended for domains that handle no mail at all, but get
mail anyway due to typos or brain-os. There's no hidden agenda.
Really.
* It has been widely implemented in Exim, Postfix and other MTAs for
nearly a decade. If there were severe damage, we'd probably have
noticed by now. The fact that it's widely implemented suggests that
people find it useful.
* The part in the draft about sending and receiving was confusing
and unhelpful, so I rewrote it. Now it says you SHOULD NOT send mail
from a domain that publishes null MX. This is both on principle,
don't send mail if you don't want an answer, and practice, since many,
many MTAs reject mail from domains without a resolvable mail server.
(Remember, SHOULD NOT means don't do this if you want to interoperate.)
R's,
John