I've officially had it with GNU Mailman. Not only is its interface hopelessly cluttered with a bajillion cryptic options, it's just downright flaky. It usually works just fine, but whenever it suddenly decides to not work, it gives no warning whatsoever nor any feedback on what went wrong, and the only available remedy is to attempt random voodoo with the above-mentioned cryptic options. The truth is that Mailman is just not designed for what I want it to do. By default, the lists created with Mailman are discussion-style lists where all members are expected to participate by posting messages to the list. But for RCBMP, I need to provide an announce-only mailing list, where only one person sends messages and all the normal subscribers only receive the messages. I've had to twist Mailman's arm viciously to get it to behave as an announce-only list, and I'm sure I've screwed up something stupid that's buried somewhere under that huge pile of poorly documented and mysteriously interacting configuration directives.
So I've decided to switch the RCBMP mailing list to Dada Mail, which provides announce-only mailing lists by default. I've installed it already, and I only have to import the subscriber list and archives from the Mailman installation before I can flip over to the new list manager. I expect Dada to be a much better fit for my needs.