Went through ORD on Monday, and it's the first time they actually looked for the CBP sticker on the inside back cover. They said it's supposed to be checked every time. Not sure why, since you scan you fingerprints and passport so they know you're in the system.

Priority labeled bag came out in the first 10, I was on my way from plane to bag recheck in only a few moments. (But they neglected to put my bag on the next flight, so delivered it at 2 am.)