This was a heavily scripted production. What the viewer will see is a seemingly spontaneous “investigation” where the UFO Hunters team goes out to Area 51 with an open mind and sees what they can find. However, any real investigation implies the ability to change course. Your path on each step of the inquiry is determined by what you just discovered in the previous step. You can't “script” a true investigation. You can only script a movie or other entertainment product.
The script in this case was rigid and demanding, and it was written before anyone from the production company had set foot in the area. In fairness, the participants weren't given exact lines to recite, and no one was asked to lie or say anything they were uncomfortable with, but the “story” was determined entirely in L.A. before shooting began. Where the crew would be in every hour of the week-long shoot was strictly scheduled, with little margin for deviation. The director and producer also knew the subjects that they wanted each participant to talk about so the resulting sound bites would fit into the story. They couldn't afford to go into any other areas no matter what turned up in course of filming.
From the production company's standpoint, there was no other way. The History Channel keeps tight reins on the show, and it has to review and approve each story before shooting begins. Any significant changes also have to be approved by them, which is a huge bureaucratic burden. The production company is also trying to turn out a complex full-hour show on a grueling schedule, and it has to be exciting—a real ratings grabber—or the show will eventually be cancelled. These pressures tip the scales from reality to fiction, because fiction is so much easier to control.
Even though you might not consider “UFO Hunters” a paragon of journalistic integrity, it does bring into question just how truthful are other journalistic investigative shows.
Just something to keep in mind …