Default [Q] How serious is the 'cracking' issue?

I am very keen on the Z2 as my first Sony phone but the reports I have read about Z1 phone screens randomly cracking on their own has me worried. How serious is this problem really?

Is this just the 0.1% of phones that the people are complaining about? Or is it more than that. I am assuming the screen used on the Z2 is the same as predecessors.