Unfortunately, no. What is even more annoying IMHO is when people post
the exact same query to multiple NGs without cross posting. Neither
should be done unless you have a good reason to cross post, i.e. you
have breaking news about a brand new virus, etc.

Cross-posting is good if used correctly.  When posting the SAME message
to multiple RELATED newsgroups then you should cross-post.  Why should
*I* have to visit and subscribe to YOUR "home" newsgroup when YOU chose
to post in MY newsgroup?  Why would I not want to see what everyone else
added to the discussion that visited the other newsgroups where you
posted?  If it was an appropriate post into the newsgroup that I visit
then the subsequent discussion is also appropriate.  If it is unrelated
then you shouldn't have posted into that newsgroup, anyway.  Why be rude
and disconnect the replies from all respondents in all the newsgroups
you multiposted to?  You really need to hide their replies from each
other?

I've read of some NNTP clients that can count the number of commas in
the Newsgroup header to determine if a message has been *excessively*
cross-posted, or they use regular expressions to detect a threshold of
comma characters.  That way the user can specify at what number of
newsgroups they personally consider a message as excessively
cross-posted.  Nope, you can't do that with OE.  I think you could in
Xnews because it supports regular expressions so you could trigger on
something like "Newsgroup: .*,.*,.*,.*,.*" to trigger on a post that had
4 (or more) commas in the Newsgroup header.  Some newsreaders make it
option where you can specify the cross-post count threshold (don't
remember which right now).

Multiposting doesn't make sense for good posts that are related to each
newsgroup to which they are posted.  You end up with disconnected
threads across multiple newsgroups where respondents cannot see each
other's answers, so you end up with duplicated replies.  Multiposting
also wastes disk space and bandwidth for all the duplicate copies of the
same message while cross-posting just uses a link in each group to the
one copy of the message.

Worse than cross-posting are those that use the FollowUp-To header to
redirect all replies into the OP's "home" group.  The user replies but
won't see their reply because it is off in some group that they don't
visit.  If the message were cross-posted, there would be no need for the
FollowUp-To because the OP would see the replies in whichever "home"
group they prefer to visit while the respondents would see the thread in
whichever group they prefer to visit.  There are some newsgroups where
FollowUp-To has a good use but in most cases its use is rude or abusive.
Few users use FollowUp-To and for most of those that I've seen that use
it, it often is to redirect the expected negative replies off to some
*.test newsgroup or to flood an innocent or unrelated newsgroup with all
the replies.  I would love if Outlook Express would flash a warning or
highlight a banner when I loaded a post that uses the FollowUp-To
header, or better yet if it had a decent rules set where I could delete
any posts that used this header.  If they want to ask in my group then
they should expect to discuss it in my group (well, make it visible in
my group).

I'm not a net cop so don't take anything I say as law.  Rules are just
that and can be tough to enforce and don't always have all participants
in agreement.  Below are just my preferences or dislikes:

- FollowUp-To is usually bad.  If you didn't want to discuss the topic
where you were attempting to attract respondents then why bother posting
there?  Be a snob and stay in your own "home" group if you don't want to
share.  I hate replying to a post that uses FollowUp-To, marking it with
a Watch flag to monitor the discussion, but to never to see the
subsequent discussion because my reply went somewhere unexpected.  For
those that use FollowUp-To, I retaliate by replacing the Newsgroup
header with all the [appropriate] newsgroups that were eliminated in the
FollowUp-To header.  Oh yeah, tit for tat, Mr. FollowUp-To user!
- Multiposting is bad.  That is sending duplicate copies of your same
message to different newsgroups.  If those were related or appropriate
newsgroups for your post then why do you disconnect the threads for
each?  You waste disk space for the multiple separate copies of the same
message, you increase bandwidth for everyone that retrieves that same
post, and you slice one discussion into many.
- Excessive cross-posting is bad (since the next point becomes likely).
The more groups you add, the more likely that some aren't really related
or appropriate for your post.  Beyond 4 or maybe 6 groups, it's tough to
find any more that are truly related to your post.  If your post is so
vague that it applies to lots of groups then is it a post you really
need to submit?
- Cross-posting to unrelated newsgroups is bad. No one cares about your
politics or stance on abortion in a computer hardware group.

... but ...

- Cross-posting the SAME message to a few RELATED newsgroups is good.