Could this be a case for stripping the: X-Confirm-Reading-To: Disposition-Notification-To: or Return-Receipt-To:, lines out of the message header? It seems like this is something a SPAM gateway could handle.
I think it's a good idea to strip read receipt request headers from mailing list messages; they just don't make any sense in that context.
But more generally, MDNs and DSNs do serve a useful purpose when used conscientiously, and I don't think it makes sense to block them for all messages. The real problem isn't the notification requests themselves, but email clients that implement the notifications badly.
But more generally, MDNs and DSNs do serve a useful purpose when used conscientiously, and I don't think it makes sense to block them for all messages. The real problem isn't the notification requests themselves, but email clients that implement the notifications badly.