So they are common and no mystery
No, they are not common and it is a mystery. That is the point.
Maybe I did not explain it well. There are four players. Obviously, we each see our own "aiming" lines and ball flight path when hit.
In my case, whenever player 4 was up, no matter whether he was hitting first or last, his aiming lines, and ball flight path, was displayed on my screen. No one else but player 4 and mine. After he hit, his path line would stay on the screen whoever was next up. It did this for each hole.