I find this morning a message on the URN WG list
by Alfred Hines on RFC 6329, which has a new (AFAIK) convention on
normative language
3. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
The lowercase forms with an initial capital "Must", "Must Not",
"Shall", "Shall Not", "Should", "Should Not", "May", and "Optional"
in this document are to be interpreted in the sense defined in
[RFC2119], but are used where the normative behavior is defined in
documents published by SDOs other than the IETF.
I am not sure this is in the direction of greater clarity. Should
there be a need to
overlay different degrees of normativeness onto a text, XML would
probably be better bet.
Whether the previous sentence is normative or not is left as an
exercise for the reader.
By my count, there are also two lower case "must"s and six lower case "should"s
in there. In a document with compliance language this complex, those SHOULD
have been eliminated.
Be that as it may, this is asking more of the convention that it realistically
can be expected to deliver. I don't know the circumstances behind this
document - maybe there was no alternative - but the right thing IMO is to
try and avoid having to do anything like this.
Ned