Adaptive Equipment problems of the 2009 Mercedes Benz C Class

I purchased a 2009 Mercedes Benz c300 luxury sedan in October 2008 in atlanta, GA. I drove the car off the lot with 37 miles on the odometer. I house the car in my garage. I'd had the car in my possession for a little less than two weeks when I woke one chilly morning to discover a crack in the driver's side mirror. I immediately phoned the dealership and was told to bring the car in for evaluation. Service assessed the damage and advised me that they'd recently (the day before) become aware that the heating elements were cracking the mirrors in the C Class models. They then apologized for the inconvenience, gave me a loaner car (free of charge) while my car was being repaired (free of charge), and advised me that, although Mercedes Benz does not allow preemptive repairs, they would repair the passenger side mirror (free of charge) should it crack in the future. They told me that the passenger side would be fixed even if the warranty had otherwise expired. The part repaired was the auto defrosting/ dimming driver's side mirror. I'm unsure if this defect is exclusive to the C Class models.