>The whole purpose is to shoot people for five minutes and see what happens. What invariably happens is somebody either tries to put on a pose, but they end up being more themselves later, they drop everything because the length of time is absurd. Finally, you see the real person behind the facade.
I actually use this method when taking photos. It works really well. You can also pretend to just take longer than expected while holding the button down. (as long as the camera is silent)