Originally Posted by
joshwex90
Can someone please explain how duty free purchase is permitted even after pre-clearance?
Furthermore, regarding luggage, what's stopping someone from hiding things in their luggage? It seems from the video posted regarding DUB that they just show a picture of your luggage, but don't bother opening it up.
They can do an inspection of your luggage after you check your bag, or before it's loaded on the plane. They ask you to confirm, so in case you have something in it you've admitted it's your luggage.
It's not that different from the US--they don't have most passengers open their bags at the customs check. If they have a suspicion (or more) they may give a secondary screening.