From the consumer nation point of view, the ideal situation would be to "stop the drugs from ever reaching shore." When authorities in producing or transshipment nations can be notified of an impending shipment, they can intercept it even before it has left their territory. This can preempt a lot of problems.
站在消費國立場，如果能夠「拒毒於彼岸」，在毒品尚未出轉運國的國境時，就通知該國警方就地攔截，借力使力，可以省掉許多後續的麻煩。