Unless I am mistaken, these reminders are called "notiFLY Pre-flight Reminders" and there are two types:
1. "Your flight is now ready for check in online. Please find below the flight you will take in the next 48 hours."
2. "Please find below the flight you will take in the next 48 hours. Kindly note that the flight is not available for Online Check-In."
Personally, I have no problems with a friendly, gentle email reminder for my flights whether or not online check-in is available. On this basis (and on this basis only

) I am not satisfied that
mayodave has proven his case beyond reasonable doubt.