WGT,
In the midst of this grid on vs grid off conversation, there is a point I would like to make. I would like to see when putting that the grid and the alignment stay on during the putt and the replays for the player that putted. That way you can see where you aimed and what effect it had on your putt. I do not believe anyone else should be able to see it, only the person who is putting. This way you can learn from your own mistakes.
I understand what people are saying about wanting to view the grid while someone else is putting, but I believe that watching their putt without the grid and where they are aiming for should be enough. Anymore than that, with a grid showing, I believe would be a unfair advantage for whomever is putting last.