Most cruise ships also have security personel. The ports are notified and permission granted in advance.
I wonder what the process is. If all we have to do is notify the port captains, then that’s where we ought to be focusing this discussion. Maybe it’s only a matter of obtaining permits. I live in the US but have hunted in Mexico and there’s a process for obtaining permits and transporting guns into the country. I always have the guide service take care of this for me. Mexico is one of the worst countries to deal with firearms too.