I recently took a look at the BMW winter cover and their instructions are: "the cover may stick to the vehicle in cold and freezing conditions, if this occurs use warm water to loosen the cover from the vehicle".
By the time I have done that I could have scraped.
Looks like it's a garage or a scraper.
Another issue is; when it rains and then shortly after freezes, the frozen water droplets are sitting in the gaps between the folding roof, therefore once you set off I hear them cracking and loosening - let's see how strong that clear coat is!
The answer is to live in a warmer climate or garage a car. I'm so envious of you guys & girls in California/ Arizona etc...