He was being followed. The minute he boarded a boat the USCG would be enroute with a cutter to intradict and perform a thorough safety inspection in international waters, perfectly in line with their law enforement and maritime safety duties.
How many of those other countries have people who lost money? What are the odds that some of the people he ripped off have very muscular friends who want to have a private chat about repayment timeframes? What are the odds that they know the kind of people you’d need to get fake ID or live undercover?
There was talk that he was followed around everywhere in Bahamas by the police.
Like I said, there are ways to keep someone on an island without arresting them. Especially in this case, what was he going to do, sue?