I too always drive with the blind open. My sunroof creaks more than rattles, especially on poor surfaces. If I shut the blind I get relative silence. I'm not sure whether the blind also has a slight rattle. Interestingly during wet weather the creaking stops, I imagine the water is acting as a lubricant. I've used a silicon lubricant on all of the rubbers that I can get to, this helps for a while.
As a previous person said, it's probably the early models that are affected, I too had the infamous tailgate rattle that was fixed using the TSB that Kia issued. Not convinced about the dealership being able to fix the sunroof though as another Stinger owner tried this route, they removed the sunroof and actually made it worse!
I feel it's not bad enough to worry about.