- πΊπΈUnited States cedewey Denver, CO
I think the best resolution to this would be to continue displaying the "Receive content follow-up notification e-mails" checkbox on the user's profile settings page, even after they've lost permission to create new content. They might want to continue receiving notifications for the content they did author.
Since the notification setting is removed if the user's profile is saved, after they've lost the content creation permission, it could be confusing to them as to why they're no longer being notified of new comments on content they authored.