But an RFC that defined Precedence properly, set out the approved usages
and deprecated the rest as obsolete might solve the problem.
not if the "bad" usages were too widespread. especially given that
most of the uses of precedence are MTA functions and do not belong
in the message header.
And in the case of precedence, even if you eliminate the usage that doesn't
belong in a header field (control over delay notifications), you still have two
different camps with incompatible views of how the field should be used
(in X.400 terms, priority versus importance).
Ned