You'll notice he keeps suggesting his opponent's throws. He demonstrates the game to the first player with scissors, who then throws scissors. Then he demonstra

You'll notice he keeps suggesting his opponent's throws. He demonstrates the game to the first player with scissors, who then throws scissors. Then he demonstrates how "rock smashes scissors", so his opponent thinks "Rock!" and throws it. Later in the video, he flashes scissors for no apparent reason before a throw, with success. Watch the video, he 'seeds' his opponents throughout.