On Aug 30, 2025, at 07:15, Christian Huitema <huitema@xxxxxxxxxxx> wrote: > > Not that SHOULD effectively means "MUST UNLESS". That is, "You SHOULD do this" is equivalent to "You MUST do this, unless you have a very good reason not too" ... but the reason is generally left unstated, except in the "SHOULD but MAY" construct as in the examples above. For a previous message, I asked an LLM to find BCP 14 SHOULD/RECOMMENDED usages without stated exception conditions, for example in RFC 8949. It found some, including a NOT RECOMMENDED in https://www.rfc-editor.org/rfc/rfc8949.html#section-3.4-10 Good to know that an LLM can help finding these. But in this case, the whole paragraph is there to alert the registrant (who is the one addressed by the NOT RECOMMENDED) about the undesirable consequences of an exception to this NOT RECOMMENDED. So I think in this instance we are well within the spirit of what is being discussed here. This makes me not so sure we want to enshrine specific phrasings of the "You SHOULD do X because if you don’t, you get Y, which is less preferable because Z” (here: You SHOULD NOT do X̅ because if you do, you don’t get Y̅, which is preferable because Z) into further rulemaking. Grüße, Carsten
