[Mailman-Users] How to track down someone mislabeling msgs as abuse?

[Richard Johnson]

I have a mailing list which has 51 members, all friends of mine.  We use it to communicate on things related to our history club.  About 1-2 times a month, I receive an automated message from AOL's abuse list, saying that someone has marked one of the messages as "abuse".  Unfortunately, there's no way to track down who this could be, since there are about 5 addresses on the list which are AOL addresses.  All I get is this:

Feedback-Type: abuse
User-Agent: AOL SComp
Version: 0.1
Received-Date: Mon, 25 Jun 2018 10:04:00 -0400 (EDT)
Source-IP: 98.173.52.230
Reported-Domain: mischievous.us
Redacted-Address: redacted
Redacted-Address: redacted@

Along with also a copy of the original message.

Using the "Received-Date" header, I can see that it looks as if the timing would point to one particular list member, but he says he's not doing anything like that.  (As a matter of fact, he has told me, on a few occasions, that he didn't even see the message in question at all!)

I've read that some people have addressed this by inserting a unique string at the end of each person's message.  I don't see a way to do this with Mailman 2.1.22.  Would something like this be possible with more recent versions such as 2.1.27, or even the latest 3.x version?  Are there other ways to address this?  I don't want to reprimand the person, I just want to educate them to not mark list messages as abuse!

Any help would be greatly appreciated!

/raj