Has anyone else had luck getting this warrantied at the dealer?

I noticed this rust last spring and the GM dealer told me they couldn't warranty it because it wasn't a body panel, and it hadn't rusted through. I'm hoping that I can go back later (when it's crumbling) and claim that as 'through'.It sure seems like this shouldn't be a place you'd have to worry abo...

Once in awhile, I notice my license plate rattles when the doors shut. I only notice this when I'm behind the vehicle and someone closes a door.Also, there is a cabin pressure vent in the trunk, on the drivers side. It's covered by a spring loaded flap. Perhaps you're hearing that flap flutter as th...