With the various SWEN viruses and other things, the automatic reply-to: gpc@gnu.de field seems to be missing on anything delivered here (cbfalconer@worldnet.att.net).
Way back when I recall there was some way to set this option on the list, but it is long forgotten. I think there was also a problem because my from: address did not agree with the address to which the mail is delivered.
Some items are arriving with that field set here, but so far it is only replies to my own articles. See the "Status of GPC" thread.