You're playing against a computer, of course. (Stupak used this promotion, what 20 years ago?) I'm guessing the computer is set to let the contestant win once in a great while, hence it will keep the customers coming in and will also create a good PR news story. I don't believe anyone ever won with Stupak though??? Since it's a pure promotion vs. a gaming venue, I believe it can be "rigged" anyway they want it. Tic-tac-toe was one of the first things computers were taught to do, by the way, as early as the late 60s/early 70s, since there are a finite number of combinations and it plays just like a logic puzzle.