Originally Posted by
poisson
I wonder if these questions actually stop threats. Do they think that terrorists are unable to lie?
"No, my bag was packed by our expert bomb maker."
It's not about security it's a customs question.
If you say you did not pack your bags then if they find something you haven't delceared then ignorance can be called upon (perhaps unsuccessfully) as a defence.
If you say you packed them, and there is a pound of pork sausages then you've also lied, and more likely to be fined.