I remember being told by a BA pilot some 35 years ago that at that time there was no check made at all of the duty free items loaded or unloaded from aircraft. The majority of the proceeds of the sales of duty free goods were regarded as legitimate staff perks and went straight into their pockets.
It looks as though not all the loopholes have yet been closed. If a random search turns up this haul, how much must be going undetected ?? Why have management not found a way of controlling these sort of problems ?