MacBook Air screen cracked

Has anyone else experienced their MacBook screen cracking for no reason? Mine was on my desk and when I opened it again, the screen wasn't working. I took it to the Istore who then sent it to the service centre for assessment. They emailed me to say there is a small crack on the screen and sent me the images and the quote to repair.

We checked the photos Istore took of my device only to find that it is in fact cracked. A tiny crack. How does this happen???

Apple insists that it has been dropped or knocked, which is impossible. There is also no visible damage to the device.

Please tell me I'm not the only one this has happened to?

I am gutted!