Disagree. The police interviews are designed to get people to say things that will get them convicted. This is a hackable system -- a social hack, but a hack nonetheless. (It might also be argued that the real hack is the police interviews where they trick people into giving up their 5th amendment rights.)
Also, the video is extremely interesting in its own right.
That's a good point, but I think it's a stretch to argue that this is on topic. If the point of the submission was the social hacking aspect it might be better received if the headline reflected that. As is, a submission like this would be much more appropriate on Reddit or Digg.
Yes but if those articles come to Hacker News so you don't have to go to Reddit, why would you keep using HN?
The best way to know if something is off topic, and indeed the best reason not to post off topic stuff, is if you think the community will spend more time debating whether the article is on or off topic than the article itself.
Also, the video is extremely interesting in its own right.