2003 envoy liftgate protector

Has anyone else experienced this? My liftgate won't open during the snow season, which makes it very difficult to put objects in the cargo area for transport. I've taken it in to the dealer for warranty they replaced the protector last year (the first year I owned the vehicle), and the same problem has happened again this year. The dealer does not want to warranty the part this time and now the glass to the liftgate is now cracked at a cost of $1900. and they are saying it is my responsiblity to foot the bill. It seems awed that a suv of this caliber cannot withstand the elements for which it was designed, I guess it does not like the snow.

I have a '04 XL and the liftgate one day in December just binds on the roof. Turns out the protector is pulled up because I had just taken it through a car wash that day. Dealer replaced under warrenty and everything is fine, and have taken it through the same car wash twice now with no problems.
So mabe your protector is getting pilled up by the car wash?

Yeah I'd look into that too. Doesn't make any sense that the weather would cause this.