I think this has the same problem than any kind of self-conditioning. I watched the video and the social community and gaming thing seem actually motivating, but I'm not sure about the punishment because you can always take the wristband off. Maybe there's a commitment and social pressure not to take the wristband off, but ultimately you yourself are responsible for keeping the wristband on your wrist and this is basically self-conditioning. Yvain made a good post about it.

Suppose you have a big box of candy in the fridge. If you haven’t eaten it all already, that suggests your desire for candy isn’t even enough to reinforce the action of going to the fridge, getting a candy bar, and eating it, let alone the much more complicated task of doing homework. Yes, maybe there are good reasons why you don’t eat the candy – for example, you’re afraid of getting fat. But these issues don’t go away when you use the candy as a reward for homework completion. However little you want the candy bar you were barely even willing to take out of the fridge, that’s how much it’s motivating your homework.

If the zap had any kind of motivating effect, wouldn't that effect firstly be directed towards taking the wristband off your wrist and not the much more distant and complex sequence of actions like going to the gym? I don't think small zap on its owns could motivate me to do even anything simple, like leaving the computer. Also, I agree with Yvain that rewards and punishments seem only have real effect when they happen unpredictably.