That's an awesome idea.Who cares about filming games with it? Any headcam can do that. Where it would be useful is having a HUD. You could use it to see anywhere on the field that a friend was filming with their glasses/phone/whatevs.
Could cheat like absolute f**k.
And I agree about filming with Glass.. pointless - just an expensive headcam, that's not what it's good/designed for. Yes, it can, but it's primary use is as a display. In a big game, showing you proximity to other players would be hilariously cool.