What about Catfish?
I haven’t seen Catfish, and don’t intend to. But hey, it’s the internet, so I believe that makes me fully qualified to offer an opinion: the footage is, for the most part, real, but the filmmakers knew what was going on early on and manipulated the events to their liking.
Does it matter whether it’s real? Yes, it does. All documentaries expose the viewpoints of their creators to some extent, but my guess is that this one crosses far enough over the line of manipulation to make it worthless.