Not really the point: that is a tongue-in-cheeck trick, as we know how to solve that problem - but it takes using different stripes of the screen, whereas in the demo they are before 2:00 all put in the same stripe...

At that point we go "Ah."

(It's very normal in illusionism: the practitioner states something that puts you in the relaxed mood of participation to a game you know - then actually surprises you.)