Every since 1971, the rule has held that no Best Picture nominated film has lost Best Visual Effects to a film not also nominated for Best Picture. It certainly buttresses the belief that Academy members simply vote for the movie they like in categories they don't really understand, and visual effects is arguably the most "technical" of the so-called "technical" awards (I always find that term so vulgar).
But if ever that rule was to be broken, this would be the year.
