When an address is unsubscribed, they get a goodbye email from the
     list software. Did that happen?

   I'm not seeing this.

   I ended up finding this for [1]gmkarl@gmail.com but not
   [2]0xloem@gmail.com . [3]gmkarl@gmail.com was unsubscribed by someone
   else at 1058-0500 today, after posting a partial unsub code publicly
   that I was surprised to receive, which would presumably have required
   brute forcing the server to use as it was missing trailing digits.
   [4]0xloem@gmail.com has bounce notices but no unsubscription notices,
   and did not receive nor share an unsub code that I saw.
   It was a little surprising that the bounce notices come from
   cypherpunks-owner whereas the farewell messages come from
   cypherpunks-bounces.

References

   1. mailto:gmkarl@gmail.com
   2. mailto:0xloem@gmail.com
   3. mailto:gmkarl@gmail.com
   4. mailto:0xloem@gmail.com