Not sure how workable but maybe if the constraints of thread titles allow it any thread created could automatically be prefixed with the movie name (unless it is already in the comment)?
Can't take any credit for this, just noticed Seds changed the title of a thread he created from the movie page to add the movie title and it seemed a jolly sensible thing to do.
Just putting the thunk out there .... obviously some titles such as Dr. Strangelove... would probably be problematic no matter how short the comment