Yes of course they do, but you want to see what people are buying in the duty free shops and stuffing it into almost empty hand luggage cases, some of which are rather larger than they should be, as we have all no doubt seen. Then walk through an empty customs hall and out..
Travel from the Canaries a lot and regularly see this. Didn`t happen so much when there were staff present. Ah well that`s progress for you eh.