I read an article on Cinescape and it looks like it's real. Sci-fi started doing an interview with Shymalan but apparently the interview went the "wrong" way and Shymalan did not want to participate in it anymore. Sci-fi kept on filming the documentary anyway and they're airing the whole thing: some parts with Shymalan's participation and some without.
I knew the moment it was fake I read an article about Night trying to shut it down because it was to expose some hidden secret of his. I find it funny that he's resorting to those old Blair Witch tactics to promote his film.
Now I know why they came clean before the documentary aired. You can tell it is set up. You can tell the lines were improv but the actors were given a direction to go. It isn't very good and once you saw it you would know it was faked.
You can always detect that level of "unreality" coming from phony circumstances.
I applaud a new take on what is usually standard-issue marketing, but three hours is ridiculous. Can't help but think ol' M. Night is a bit of a narcissist, what with the length, the focus, and the constant mentions of him as a "great director." Ugh.