Or, you know, you could just turf all e-mails with those "reacted to your message" Subject: headers, and not use any MS specific headers in what you send. This

Or, you know, you could just turf all e-mails with those "reacted to your message" Subject: headers, and not use any MS specific headers in what you send. This reaction thing seems like a gift from Microsoft to spammers. E-mail recipients have a "like" button that instantly generates a reply, validating that the e-mail address is staffed.