Although this film is inspired by Jon Ronson's Book The Men Who Stare At Goats, it is a fiction, and while the characters Lynn Cassady and Bill Django are based on actual persons, Sergeant Glenn Wheaton and Colonel Jim Channon, all other characters are invented or are composites and are not portrayals of actual persons. The filmmakers ask that no one attempt walking through walls, cloudbursting while driving, or staring for hours at goats with the intent of harming them... invisibility is fine.
More of this is true than you would believe.