Going from usvi to svi and needing to check in makes sense because you are moving from a duty free zone to a duty zone.

That's similar to going through customs on arrival by ferry in stt and then again when departing stt in a flight to the continent.

Warren S/V Scuba Doo
Lagoon 50 (winner of best crewed yacht under 55 feet at the St. Thomas crewed yacht boat show).

https://www.cyabrochure.com/ebn/2307/pdyrX/6642/4///