More to the point: these are all decisions that the receiving
software can make, and make with as little or as much granularity
as you wish to envision.
You appear to be confusing localized mechanism with Internet standard. We are
discussing the latter, not the former.
Any validator is free to add whatever cleverness they wish. However the degree
of cleverness or its usefulness does not give it status within the IETF
specification.
d/
--
Dave Crocker
Brandenburg InternetWorking
<http://bbiw.net>
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