Augmented reality ad

Here is a creative idea for a web ad--one that uses augmented reality. For those of you who don't know, augmented reality involves using technology that interacts somehow with reality. In this case, the ad watches you with a webcam as you use your head to score a soccer goal.

It's a lot easier to get what I mean if you watch the video above. What I don't know is if the ad actually detects the movement of one's head or if it automatically bounces off the frame of the video--for instance, what happens if you don't move at all?

And, if you have a webcam, you can try it out yourself (I don't, so I couldn't try it) following this link.