On Mon, Dec 17, 2018 at 6:09 PM Per Bothner <xxxxxx@bothner.com> wrote:
 
>      I assume that the "should" here meant in RFC-2119 sense.  That
>      is, is the above merely a suggestion/recommendation, and not a
>      hard requirement.

Correct.  I changed 'should' to be in emphasis (italic) as in other places.
I could put an an explicit rfc-2119 link, or may be that could be implicit
to all SRFIs - or may be could replace it by "is recommended".  (The
latter has the advantage of being compatible with rfc-2119 link but is
reasonably clear without referencing rfc-2119.)

Arthur, what do you think? 

I'm happy that people are using RFC 2119 terminology more and more consistently, but I hesitate to require it or make it implicit.  But if you're consistently using RFC 2119, please do include a reference to it.