If the ball bounces and is collected by the same player it's far easier to tell what path it took and in which direction it travelled.

As has been demonstrated on sky many, many times - different camera angles can make a legal pass look forward and vice versa. That is why video refs can't judge them reliably and consistently (not that referees and touch judges can either, mind!)

Apart from the fact that one decision is based on the absolute position of the players and the ball and the other is based on the relative position of the players and the ball, you are right, they are exactly the same

Good quality ones are. They use them in geology to measure land movement of millimetres over long periods of time.

No I said the system you proposed wouldnt be possible. To avoid confusion i mentioned Hawkeye the company, not hawkeye the system.

Even for you Smokey, that's a poor attempt to wriggle out of something you've said!

Its not really complex to say there may be an engineering solution for accurate judgement of forward passes, but your's wasnt it.