I was waiting to board a flight from Shanghai to Hong Kong yesterday, and while I was sitting by my gate, a woman approached me asking if I could take one of her luggage with me because she had "too many". I said no, and thought it was weird. The airline we were flying has a strict luggage policy and they made me check my carry-on before going through security (I wasn't allowed a carry-on), so I wondered why they let her go through with too many bags. When we started queuing to board, I saw several other people, apparently all from the same group, asking other passengers to take their luggage. I noticed one of them had a duty free bag full with several bottle of the same perfume.
What were they doing? Have you ever seen this?
ETA: I know you shouldn't travel with someone else's bag/a bag you haven't packed yourself. That is not the question.