Those who found fault with the most recent "twist" on Homeland don't know enough about thriller plotting. (Thompson on Hollywood)
"Undermining the believability of what we see" (a sore point with the above sorehead) is a staple tool in the thriller writer's kit, and not only of those on the far end of the noir spectrum, such as Woolrich and Bardin, whose anti-heroes are often unreliable to the point of psychosis. A more mainstream example, Robert Ludlum's novel "The Bourne Identity," though not the film version, employed major efforts of misdirection to convince Bourne himself, and the reader, that the amnesiac fugitive is actually Carlos, the Most Wanted Terrorist of the era in which the book was written. Does that make Ludlum, too, a "cheater"?