I can't find anything about MCT in the tariff. The closest is this (Rule 90, Denied Boarding; Part G, Compensation):
A passenger is not eligible for denied boarding compensation if: e) the passenger has been rebooked on another flight by the Carrier as a result of a delay or cancellation on the passenger’s arriving flight.

The AC domestic tariffs seem to define "denied boarding" in two different ways. Rule 90 defines it in terms of oversold situations: "Definition of Denied Boarding: A passenger is denied boarding when the number of seats that may be occupied on a flight is less than the number of passengers who hold confirmed reservations, have valid travel documentation, and have checked in by the required time and presented themselves at the boarding gate by the required time." But then in Rule 100 "denied boarding” is defined as "inability to provide previously confirmed space (denied boarding)”. The word "previously" was key in the Nova Scotia court case, as it left AC responsible for its auto-offloading of a passenger who might not meet MCT thresholds but otherwise showed up on time for her/his "previously" confirmed flight.