If posters would take the time to evaluate what they see in these diagrams, they'd understand how difficult it is to just watch a game, and evaluate how well a player has done. There are some instances where it's obvious they made a mistake, but in some cases, their objectives in a play actually takes them out of what a person might think was where they should be. When that happens, quite often it's someone you didn't even see on your screen, who blew their assignment.
As a coach, you watch film/tape, that covers the entire scope of the playing field, so you can see what each player is doing with each call that was made. Then you grade them on whether they met their objectives or not on that one play, and write down any notes that you'll want to use to critique that player on where they may have made a mistake in technique, or all other facets of their actions. Then, when you practice, you point out the mistakes as you go along, and get the players to modify their actions the next time the play is run in a game.
Whitewater is a prime example of a program that insists on discipline on every play. Each player "must" carry out their assignments. In a way, the players who are key in more cases than any other position are the tackles. They expect them to hit their marks constantly, and not be duped by the defense across from them. Of course, when you study the diagrams, you'll see that being an offensive lineman at Whitewater, you have assignments that you need to understand, because there are so many options as to what your assignment will be, depending on the defense, and what happens when the ball is snapped.
They win! They win a lot! I've stood on their sideline during practice, and watched them run through plays to get them right. They want 100% participation on every down. I've stood there too, during a few games, and their players are ready when they take the field. If they make a mistake, they are told about it, as soon as they come off the field, and are informed how they can avoid it happening again. They are coached for every minute of every game.
Dig into the diagrams, and learn all you can. This is an opportunity that a lot of people who don't coach never get.