You seem to be saying that the meaning of this clause in the standards is undefined (or is it implementation-defined?) I have no idea what the authors of the s

You seem to be saying that the meaning of this clause in the standards is undefined (or is it implementation-defined?) I have no idea what the authors of the standard would have in mind in putting a non-binding constraint in a standard, unless there's a faction that hopes to make it binding in the future, and hopes this will pave the way.