It has been known for TP to credit on flights that have been booked and then cancelled.
I have never had TP credit for flights that I have checked in for and not taken.
Yesterday I checked in for a LHR-AMS and boarded the flight. We were then told by the captain to expect up to 3 hours waiting on the ground due to a problem at AMS so I just got up and offloaded myself. I wonder if those points will hit.