Because they aren't flying a flag of the country in which their boat is registered. All boats do this. Not doing this is like flying a plane without filing a flight plan.
Technically when you don't fly a flag you are considered a pirate. Clearly they aren't pirates but they are smugglers. There is no other reason why you wouldn't fly a specific national flag. You can complain about the rules of engagement and that is fine. However, posts like yours aren't exactly rooted in honesty, competence or good faith.
Technically when you don't fly a flag you are considered a pirate. Clearly they aren't pirates but they are smugglers. There is no other reason why you wouldn't fly a specific national flag. You can complain about the rules of engagement and that is fine. However, posts like yours aren't exactly rooted in honesty, competence or good faith.