In Rugby, if the ball carrier is running at high speed, and then passes the ball to a player behind them, the ball might still actually travel forwards due to the the momentum of the passer, but end up behind them, and the recipient still be behind them when they receive it.
If this happens, is this considered a forward pass? i.e. does the referee look at the flight of the ball relative to the pitch, or relative to the player who passed the ball?
And if it's the passer, what if the passer stopped running when they released the ball? Now it would appear to move forward relative to them, and appear as a forward pass even though the pass would be the exact same if they had continued running.