I talked to the person who initially installed the first roundup on one 
of our systems. He said he was aware of the possibility of having a NOSY 
reply get inserted into an issue's messages, but opted out. The reason 
was that people add lots of cruft to their email: the repeated history 
of replies and confidentiality notices that aren't germane to the issue.

I understand the concern about exposing the author's email in a large 
site.

Perhaps another [mail] or [nosy] config option could be added to allow 
the Reply-To to go to the author or roundup?

If you agree with this compromise I'll work on it and attach my result 
to this issue.