Maybe you should like, watch the video. Or admit they don't always dive. I find it amusing people say they always do, when often going over is done not in order to gain advantage, but because you're running full-pelt and slight contact sends you off balance. Or you're trying to avoid injury.
But obviously unless you're rugby tackled to the floor you shouldn't go over. Obviously.
Seriously man. It is almost a certainty that if you are running full speed and someone clips your ankle that you will fall over. Diving does not happen as often as people seem to imply.