Just saw Llanelli beat Munster, and there was talk about a forward pass for Munster's first try. This vid http://www.youtube.com/watch?v=RgMlDy2jP9s explains something I never understood before. The point is that, because of momentum, it's almost impossible for the ball NOT to move forward relative to the ground if a player is at full tilt and passes across his body. It becomes obvious with the example of passing back over your head - nobody would say it's forward, but the ball still moves forward. So the ref should judge the movement of the ball relative to the passing player.