Get flight status notification, unless late or delayed

Apparently, on the Southwest Airlines website, you can't get flight information notifications unless you sign up well before the flight is scheduled to leave. If you find out the flight is delayed, and then decide you want to be notified, you get this piece of broken logic:

The flight information that you entered is for a flight that has either already arrived or departed, or the notification time that you selected is too close to the arrival or departure time.

Any programmer would advise against the ambiguity introduced by those "OR" statements.

Does it mean you can't request notification of arrival time after the plane has departed?