Originally Posted by
falconred
Too late now, but I would have taken the cap (I always do). There's no way a bottle cap is a prohibited item and I don't have to justify why I want the cap, even if I have to surrender the bottle.
If the TSO is truly discarding the bottle (and not retrieving it later), he/she won't care if it has a cap or not.
If the TSO is planning on appropriating the bottle for personal use, it will be worthless without the cap.