yeah just be polite and simply answer what they ask and 唔好寸佢地呀!even if you think they ask something very irrelevant or stupid, they are just following the procedure (sometimes)
p.s. I don't work at the customs
The custom won't have time to even determine if the movies are copyrighted or not. If I have my iPod, would they check to see if the songs I have are legally downloaded?