No, there actually exists an email header to request a notification email to be sent back whenever the original email is read. This header exists since at least

No, there actually exists an email header to request a notification email to be sent back whenever the original email is read. This header exists since at least the 90s, and for instance Thunderbird has options to both set that header, and to honor that header (sending the notification emails). I vaguely recall that the default, at least when I last configured Thunderbird, was to not add that header, and to ask before sending a notification email.