These drug interdictions at sea are almost always because someone dropped a dime on the enterprise or intelligence/police work before the boat left its loading point. Easy to get cooperation of a foreign government
to allow boarding and seizure with that information.
Have heard that even the drug supplier will turn in unaffiliated smugglers. The supplier gets the money
, the loss of the goods puts upward pressure on the market for future sales and they make out on the value of the next shipment. It's no longer a business for the independent contractor/entrepreneur.