The USA is going through one of those periods where they sometimes make people go through the 'did you pack your own bags?' 'have they left your sight?' circus of fools routine while land side.
So do ask in the check-in area if Question Time is on for the day. I know that Sky Team partners put a small sticker on the back of the passport after the quick screening is complete, and security and gate agents further down the line do check for the sticker before letting you proceed further.