Cracked windshield

Drove by '06 coupe into work one warm day about 3 weeks ago and parked it in the out of the way corner. At the end of the day when I was leaving my heart stopped when I saw about a 15" crack in the windshield on the driver's side that spanned about 3" from the bottom (looks like all the way to the end of the glass) to across the center on the windshield (kind of behind the steering wheel). IT WAS NOT THERE WHEN I PARKED IT and security cameras shows no tampering (I had that checked in case it may have become a police issue). I inspected and the dealer did too and found no sign of a chip that may have created the crack. The service manager agreed that it looked like a stress crack to him, however that would have only been covered within the 1st 90 days. Per him, GM warranty does not cover the glass. Car is about 9 months old with ~11,000 miles. They suggested making a claim with my insurance company.
Anyone else have any issues with the winshield?