Owner on interstate at posted speed (65) heard explosive sound of the sunroof exploding. no other cars were ahead or alongside, and no evidence of a thrown or dropped object was apparent at that time or afterward. fortunately the sunshade shielded her from most of the broken glass. dealer called it an 'act of god' and would not honor a warranty claim for the damage ' estimated at over $1,100. insurance company is covering all costs, including rental car, until repairs are completed.