My Macbook has a hairline internal crack.

My new macbook has an internal crack in the screen. I haven't dropped the machine or placed anything heavy on it. I shut it down and moved it to another room where I keep it when not using it (in my cupboard over a pie of clothes). When I reopened it I found this crack. The laptop has never been dropped or suffered any trauma in the past. I do take it around with me a lot but it's always in a protective case. Is this possible? That this happens without anything wrong done to it? I have an appointment with the genius bar tomorrow but would like to have back up if anyone else has this. I live in Istanbul and don't know if they have the recent tools to check for trauma (there is a dent machine). If they have then my argument is possible as they won't find any dents. Once repaired will this happen again? Is this a design fault or something like that?