Perhaps more of a European mega-rich habit, not especially applicable to the US, is the practice of just taking the mansion, helicopters, and cars with you on a super yacht.
I'd forbid those things in territorial waters. They bring no money to local communities and are glad to do things like ignore nature reserves or go with motor boats where people are swimming, which is of course illegal but they don't care.
* https://theitalianseagroup.com/
* https://benettiyachts.com/
* https://www.sanlorenzoyacht.com/