Excerpts from Thomas Sawyer's message of Sat Jul 16 05:38:13 +0200 2011:
> I ask because it did not show up in the Google Group, nor in the 
> ruby-talk archives.
If you use mutt, sup or the like you can edit all header messages.
Then you can keep "In-reply-to" fields by accident when replying to
an arbitrary message. My sup showed "one unreceived message".

Not sure whether this helps you.

Marc Weber