In message <20040105115510.GA4980@cyclonus>, Christian Biere writes:
>[Please, don't set the Reply-To header to an invalid address!]

I've done some testing with various MUAs and it appears send-pr is the
culprit.  Neither mail(1) nor another MUA I tested set Reply-To.  It
appears that send-pr sets Reply-To: $LOGNAME, which must get the hostname
appended to it automatically somehow.  Although it is acting differently
than other MUAs, fixing it is clearly a MTA configuration problem
(complicated by the fact that I'm on a DHCP address and thus have a
clearly bogus hostname), so this is the last I'll mention it in this
thread...

If any of my subsequent emails have a bad Reply-To, please let me know
via personal email; perhaps my tests are flawed in some way.