I just finished doing the rotors and pads on my personal van on Friday. This morning I get in my work van to drive 4 hours to Pittsburgh and what happens? I step on the brakes and they go to the floor. Almost rolled in front of someone.
Got stopped and did a quick walk around. Found the passenger rear inside pad laying on the ground. Not the hole pad, just the fiber part. 
The driver side looks just fine. My personal van looked the same way, passenger side was warn down to nothing but the driver side had another 40K left on it. GM needs to look into these caliper brackets and get this fixed.