Chucking contraband on an isolated taxiway in the dark or dropping it in the woods on the way in is a pretty good smuggling technique. The hard part is finding the self-control to stop picking up the easy money (the most addictive of all substances); so, many end up doing it again and again until nicked. Do it enough times and word will eventually get out and the authorities will be waiting. And if some shady character suggests such a money making opportunity, it may be because they are unsure whether the pilot (fall guy) will be nicked next time around.