MacBook Air Screen Cracks

I bought my first MacBook Air just over a month ago and couldn't have been more careful with it. I used a case everytime it went anywhere and didn't bang it on anything, drop it or knock anything against it. So I was obviously confused/annoyed when a relatively small crack appeared on the LCD behind the screen literally out of nowhere and without anything happening to it. At my local Apple reseller/repair store they took a look at it but like me didn't have a clue how it happened. Anyway we contacted Apple and a replacement was sent.

So I've had this new Air for around three weeks and this time I've been even more careful with it, with nothing at all happening that should have caused damage (trust me, I'd have remembered if even the smallest thing had happened!).

Just now I've noticed a crack that looks exactly the same as the one before but on the oppisite side of the screen. Like before I was just sat with it infront of me, the crack wasn't there one second and then suddenly it was.

I haven't had the chance to contact Apple yet, but I highly doubt the guarentee will cover this again.

Has anyone had similar problems? If the MacBook Air is so delicate that damage happens this easily, literaly without anything to cause it, then it's just crazy and a massive design flaw.

Thanks.