Alas, a few spam mails snuck through to the BALUG-Talk list. I've deleted those postings from the archive, and also reconfigured Mailman3 so it will no longer consider Sender: nor Reply-To: headers when determining if a posting (attempt) is from a member or not. Alas, spammers will forge list member email address in Sender and/or Reply-To: headers to post to lists, and that looks to likely be what happened.