This same problem occurred to me to the 2008 RX 350 model recently but the dealership did not pay for our repairs. The inspection alone costed were approximate $2000 if we wanted to prove that nothing had hit the sunroof for it to crack. This was pretty outrageous since nothing had hit the sunroof yet it randomly shattered. Since our car was not under warranty, the dealership did not give a full inspection unless we paid for it and strongly believed that some had hit the roof when it didn't. I think Lexus should really look into this problem if its occurring to other customers as well.
