Not to good at this site yet, but will try again to post this about the rust problems.
Have a 2010 that I noticed rust on the rear hatch after about 9 months and on the bottom of the doors in about 2 years. Remembered this site so looked up and decided to go back to dealer and see what they would do.
As it was off warranty they called the GM factory rep. who OK'd it at no cost to me. I'm a long time GM buyer and have noticed the factory reps are much better at customer satisfaction then the past.
As for the rust issues;
Rear hatch emblem [which is sharp] had no gasket behind it so after time it cracked the paint. They removed old emblem, sanded down entire hatch, repainted, put on new emblem which now has a thin gasket behind it.
Doors, bottom seam was crimped but not fully welded so rust started in the seam. They opened up the seam, used some type of epoxy material to seal and then repainted.
Both look great now.