the rewrite fails GNKSA rule 13 in that it doesn't support cancel or supersede.

We can test to see if the user owns the post by comparing the From: header
to the posting profiles, as we did before.

13) Allow users to both cancel and supersede their own articles (and
    _no_ others!)

Any software that posts news SHOULD provide a command that the user can
invoke to cancel her own articles.  It SHOULD also provide the option to
supersede the user's own articles.  The software MUST guarantee that
the user cannot cancel or supersede other people's articles, as far as
possible.

Caveat: since completely reliable authentication can be infeasible, the
        best the software can do is to make a good-faith effort to
        determine whether or not cancelling or superseding is valid:
        i.e. by trusting upon its user configuration and checking it
        against the relevant header(s) in the target article.

If the software uses the English language, the text of the cancel
command SHOULD include the word "cancel", rather than non-standard verbs
such as "delete".  Similarly, in English software, the text of the
supersede command SHOULD include the word "supersede".

Rationale: People make mistakes and need the ability to revoke or
correct them; both `cancel' and `supersede' exist for good reasons. 
However, software should not encourage users to abuse the net, either
intentionally or accidentally, by sending unauthorized (`rogue') cancels
or supersedes.  The supersede option is essential: due (a.o.) to
sometimes unpredictable usenet propagation, a "cancel-cum-repost" may
behave very different from a "supersede".  News servers might also have
different acceptance policies for both.