I don't know of any "harbor" that requires people to leave. I know of plenty of marinas that have the word "harbor" in their name, my marina included, who do.
But, as much as I hate to bring up Floridaanchoring laws in any context, I wonder what the policy is or will be for mooring fields during hurricanes. From what I've heard and seen about how many were installed, I wouldn't be sure a lot of them would be capable of holding a good sized boat in a real blow.
It will be interesting to see what happens the first time with those.
I was told by bobbies mega yard st martin that they require boats which are hauled during hurricane season to have the mast removed. This requires a crane and a rigger: 2K to remove + 2K to re-install.