Having re-read it I now realise it seems the TSA immediately whisked it out of the scanner and handed it to the wrong person before he even had a chance to get through the scanner and look about for it.

My initial interpretation was it was sitting there available for him to pick-up but he forget about it and walked off, the woman later (falsely) claiming it. Hence my initial comment.

So I agree does seem a little too convenient to be coincidental.