This report says "I took the set of flashcards from my pocket and handed them to the officers."
That was done in response to "empty your pockets", a command from a TSA agent.
Paper doesn't trigger metal detectors so there's no real need to put it all into the tray the first time.
Perhaps you missed the great scandal of the 'body scanners.'
This report says "I took the set of flashcards from my pocket and handed them to the officers."