Fellow sailor crossed the course of Turkish submarine while under sail (meaning he had a right of passage). It was in Turkey's waters (!) about 10 years ago. Instead of changing course they made an emergency dive exercise.
It’s gotta be fun to have three dimensions of freedom available when making course changes.
But man, I’d freak out if I were on the sailboat watching that happen!
That said, international waters isn't actually a lawless zone. These boats are undoubtedly registered in the US, and thus subject to US law.
It's hardly uncommon for cops to tell people to back up from an accident/crime scene if they're too close.
Edit: Oh, there was another boat the parent comment was referring to.