Luke Shaw did tweet that he was OK and feeling better, last night. He had an x-ray and they were keeping him in overnight for observation. The Commentators said it was a 'clash of heads', but Shaw leans in to head the ball clear, but doesn't see the Spanish winger, who came in off the touchline. The Spaniard tries to pull out of the challenge, and it puts Shaw's head and neck in an awkward position, and that's what causes the injury.
In the Phil Hughes (Cricket) situation, Helmet design has moved on, and more protection has been added to the area at the back of the neck, and behind the Ear, to prevent a repeat. I do feel though, that that was a one-off, as he looked away from the ball AND it didn't bounce as high as he expected.
The answer (In Football)? Well, you can't stop Footballers rom trying to clear or head the ball away from danger, and, just because you get a 'shout' from a team-mate, you can't be sure it isn't a member of the opposition, trying to get you to leave it so they can score instead. I think it has to be put down as an accident, an move on.