Covert Shores reports on the first use of an unmanned surface vessel for drug smuggling that I am aware of.
This particular attempt was over a relatively short distance, and employed only a simple outboard to smuggle a small quantity of Marijuana, but I think we can expect to see more of this. The autopilot electronics are simple and cheap. I don’t expect the smugglers would worry about the more difficult problems of collision avoidance and following the rules of the road.
Obviously there would be an advantage to the smugglers in reducing the “manning cost,” Removing the crew also means, the smuggling craft could be made more stealthy. Perhaps more importantly it would mean that when a shipment is intercepted, there will be no one on board that can be interrogated, possibly providing intelligence that might lead to the leadership of the criminal organization.