By the way, the crack is not only located at the top of the housing(plastic) but also shows a scratch in the metal plate:
Not in their current form but it's impossible to say if they'll get worse.
i've email SE yesterday about the cracks and i've just got a response. They want to investigate my phone and they are going to swap it for a new one
My Phone has the crack as shown in the earlier Photos. I'm from India.
Is it problem with the heating? I will call SE guys here but I doubt if they have any idea about this.
I've contacted SE Belgium through facebook and they told me the crack is in fact a crack in the paint and doesn't affect the phone's safety...
Mine has also been sent for repair... still waiting though. Hope it's fixed permanently..
i have exact the same problem without dropping my phone -.- .
Pictures :