Bag tags, also known as baggage tags, baggage checks or luggage tickets, have traditionally been used by bus, train and airline companies to route passenger luggage that is checked on to the final destination. The passenger stub is typically handed to the passenger or attached to the ticket envelope: a) to aid the passenger in identifying their bag among similar bags at the destination baggage carousel; b) as proof—still requested at a few airports—that the passenger is not removing someone else's bag from the baggage reclaim hall; c) as a means for the passenger and carrier to identify and trace a specific bag that has gone astray and was not delivered at the destination.