Re: Gmail email blocking is off the rails (again)

On Wed, 4 Dec 2019 at 17:39, John R. Levine <johnl@iecc.com> wrote:

Or maybe users are tired of the useless monthly messages and report them as spam.

Again, these are not a user messages or regular list traffic, they're admin/moderator messages addressed to an admin of a list. Your point about the possibility of spammers forging those is taken, but I don't see that as being anywhere remotely common enough to justify a 5xx error on attempted delivery of such a message.