If the film were a real documentary, how could a cameraman film the moon lander landing? Whenever you watch a pseudo documentary and you're not sure if it's real or not, pay attention to the camera angles. If a person couldn't be at that place with a camera, you know it's not real.
Rstar, There's something you need to know. -- Novelists and movie makers have a licence to tell lies.
You can learn a lot from watching good movies, or reading good books -- but you don't learn it by believing what you're told. You learn by thinking, "Hmm, that's interesting, I wonder if it really happened." Then you do the research necessary to find out.
And go read rainnsurf's answer again. It's one of the clues.