Then the diagram should have the caveat.While I would agree that IFAB has approved the diagrams—which have been in the book for a long time—I also think people are overreading what this diagram conveys. I don’t think the diagram is intended to say that any time a GK has vision blocked it has automatically prevented the GK from making a play. Keeping in mind that the possible OS offense only occurs once the ball is headed, only Superman could have saved that shot from where the GK was in the absence of blocked vision (accepting that his vision was obstructed). This is the hard case for the Law. As I would like to see the shielding and harassment of GKs eradicated from the game, I would be fine with his being established as an OS offense. I just don’t agree that the diagram is intended to do that—if IFAB really meant that blocking the GKs vision is always an offense, it would say that in Law 11, not have the caveat that it has to be preventing a play. But if the PL has give. Instructions to call it that way, it wouldn’t be the first time they have gotten ahead of IFAB on something.
And is it only an offence if the OP is standing that close to the GK?