I've had crew join me for the Bahamas-U.S. leg who were not on the boat when it left the U.S., and I've always been cleared by phone
. I don't have enough experience however to comment as to whether what I've experienced is normal, or if I've just been lucky.
You can clear customs
and immigration at Fort Pierce, so it seems to me even if they do not accept the LBO via phone
, the worst that is likely is you will have to make a stop at the dock
I get more concerned when hitting the places like St. Lucie and up the Okechobee where there are no on the water customs
This page has contact numbers for Florida
LBO, so you could contact them if worried.