Sections 7.1.* offers degrees of advice qualified by "safely", "usually",
"reasonably" and "should". There appear to be only two concepts:
- "safely": Do this all the time.
- "usually", "reasonably", "should": This is the recommended course
of action, but there may be exceptions.
While RFC 2119 is not intended for Informational documents, this is an
example of the sort of sloppiness that RFC 2119 is intended to clean up.
At the very least, the use of three words for essentially the same concept
is poor form, and RFC 2119 can be used in an Informational document when
appropriate caveats are provided in the terminology section that references
it.
Earlier versions of this draft looked roughly like an applicability
statement, and thus
had RFC2119 language throughout. We decided that, as you point out,
it's mostly
advice, and not a way of establishing a capability within Internet Mail,
which would
be more like what an applicability statement is for.
I'm thus inclined not to backtrack, but merely satisfy your "At the very
least" clause.
I'm more inclined to leave it alone:
This is not conformance language at all, and isn't meant to be. It's mild
advice about how one might handle bad situations. We could be consistent,
and pick one word. Or we can leave the document less stilted and have it
read better. We specifically don't *want* to be precise, here, about the
strength or *exact* meaning of the advising words.
Barry