Maury show: dumb guests?

Ok so I'm not gonna argue that the Maury Povich show is fake or real, but if it is real, how dumb can some of these guest be? My example is: a man is being brought onto the show to get a lie detector test to see if he's cheating on his girlfriend, yet they show footage of him flirting with a decoy in the green room. How dumb can he be by flirting back? Doesnt he watch or know about the show and that girl is probably a decoy to catch him red-handed? they're probably actors but still if it is real how dumb can they be to fall for such an obvious trap?