Defogger problems of the 2000 Ford Windstar

I rented this vehicle from budget - I do not own it. However, we drove it the night of 4/07/00 to dinner during "blizzard-like" conditions in great lakes, IL - very windy, cold, and snowing. We had the heat on and the window defroster for the rear, left passenger-side (third window) window also on. This is a unique feature of the Windstar minivans. There are also two ceiling-mounted heating vents that direct heat into the back third of the van, including the third passenger side window which has the defroster embedded in it. I parked the van at the hotel after we returned from dinner. When I went out to the van the next morning, the third side passenger window on the left side was shattered. I phoned the waukegan police department and the officer who came out first asked if the window had a defroster in it. He said he was aware of other occurrences like this. He said he didn't think it was vandalism but instead was caused by the extreme temperature contrast between the air in the interior of the van (where the defroster and the heater were on) and the exterior air, which was well-below freezing. While the van was moving the air was constantly circulating both inside and outside the van, however, once the van was parked and the hot, interior air was no longer circulating , the extreme temperature contrast between the air on the inside of the van and the air outside of the van caused the window to shatter. While I am relieved that there were no occupants in the last seat of the van when the window shattered, I am concerned about the potential danger to others. Do you have any info about this engineering defect?>.