The customs security system at airports is the strictest, all suitcases and luggage go through an x-ray machine, in many or all airports you must go through a Millimeter wave scanner and in the customs of some countries the agents have Narcotics Trace Detection Equipment.
On the other hand, in the commercial port, not all the containers are inspected because there are many and few agents in service, the containers are inspected depending on the origin (if it is a high risk country) etc.
But here in Europe, loads of cocaine with 1000 kg always enter, the police also seize a lot, recently they seized 5 tons of cocaine in the port near me.