Update:
Before I met the guy I ran a car Fax. Learned a roofack was installed in Dec. 2011.
Seemsa piece of cloth got stuck under a moulding that leads to the roof rack and continued wedging it's way back, pulling off the moulding, getting stuck under the rack and applying pressure on the top glass panel which is not really a sunroof. Until it cracked. Comparing the DS where this occured to the PS where you could not even fit a piece of paper under the moulding or roof rack, I denied liability since the roof rack and / or moulding had to be sticking up in order to allow the cloth to wedge under it.
Probably have not heard the last. Took Photos and kept a copy of the car fax.