When I was VERY little we lived in upstate NY and went over to
Ontario, Canada for a visit. I remember that before we got to the
crossing, my folks hid a shirt that they had bought under the seat.
It was just a normal, man's oxford shirt, nothing special, but I
guess they didn't want to pay duty on it. So when we got to the
crossing, and the guard asked if we had bought anything in Canada, my
parents said "NO" and I piped up from the back seat "you forgot the
shirt under the seat."