My wife often answers these questions with, perhaps, excessive honesty.
"Yes, mum asked me if I don't mind taking a box of shortbread for her sister in Paris, she loves the stuff" etc.
She also feels obliged to tell them she's packed her electronic hair dryer and so on.
I keep advising her just to say three bags full, but she's not built that way. Always results in a trip to the screening area.