Cracked screens usually aren't covered under warranty, but are under insurance, even if the screen cracked "for no reason". (The usual reason if, the screen has curved edges, is that the glass wasn't properly annealed, but it's still not covered under warranty, because it's not possible to tell, after the fact, what caused the glass to crack. [Cracks on the curved portions should be covered under warranty, but the companies are in business to make money, not to be fair to us.])