So what happens when it *does* break?
1) The damage to the normal windscreen wasn't pretty but was fairly limited.
2) The damage to a Prince Rupert's drop is all or nothing.
3) If the inner layer of the new windscreen uses the same method to get its toughness, what happens when you wind up the size or speed of the ball bearing and break through the windscreen? Does the entire windscreen explode?
( I know that iPhone screens can be broken without exploding, so maybe it would be an anti-climax, but I'd like to see it demonstrated.)