They are not hardy in that sense. The “eyes” of the coconut quickly soak up seawater and that kills the seed. They can float long distances by sea but they won’t arrive alive.
>>. The “eyes” of the coconut quickly soak up seawater and that kills the seed. They can float long distances by sea but they won’t arrive alive.<<
Yeah, I misread part of the point — but I think there is some history of organic migration but not the long distances humans carry them.