What I saw at NCL was very open and they stopped and went through luggage of two sets of passengers that I heard the detals being spoken to the other end of the hall by radio.
They were both carrying duty free bags, one from Bangkok the other from Dubai.
It really does not bother me as I dont smoke,never buy duty free as its to much of a ball ache to carry and I prefer to buy electrical stuff in UK as I get the warranty and back up