It's that the anchorage is so, so small and with the locals there it really is all filled up. Since you are chartering in the VI's obviously money isn't going to be an issue to the 20 buck mooring fee (was that a few years ago, may be higher now) won't set you back and and ou have some secure feeling over night. I doubt the charter boat has enough chain to anchor in that hole and it is deep!

Ciao