Airport security question?

No, he is not asking that, or meant something different. Between him to you, there was a miscommunication. What he was asking or was supposed to ask was if anyone asked you to carry something across for him or would you mind putting my item in your bag just until we get to the other side? Their reasoning would be their bag is full but it's a lie. If you get caught, you take the fall. If you don't get caught, then they get their item on the other side - some illegal item, possibly a bomb. Not everyone would speak up or is aware of such criminal conduct, so they ask in case someone did accept something from some stranger.

You have selected a best answer but I will answer anyways.

The customs officer was asking if you had someone else pack your bags with or without your knowledge. If you don't know WHO packed your bags, then say someone else did.

Odd for a customs officer to ask that. Normal question from a TSA officer, though.

If you want to know why, read up on the PanAm flight 103 bombing.

You don t know if someone packed your bag?

If you packed your own luggage, your answer to that is - No.

If you re in a household where you worry about someone putting drugs or weapons into your bags - your reaction to that question may prompt the customs officer to do a search.

Just answer that nobody packed your bags nor put anything in your bags without your knowledge.