There are gas shortages and the roads will soon be clogged from people heading north. Maimi-Dade where RCCL is based out of will have school and county closures thurs and fri. We are assuming corporations will be closing offices in the area too, to allow time to board up and prepare. Maybe that is a factor in their decision as well? Not sure but I'm hoping Disney follows suit because there is no way I'm making it up there on Friday.
I doubt it is a cancel this far in advance reason on the Port Canaveral side, Absolutely on the Miami side. South Florida is going to be a nightmare for the next week even if the hurricane misses.
Part of that problem is Southern Florida has boomed in population a lot faster than the infrastructure can keep up. Nightmare scenario for those trying to evacuate late.
Unless there's a support capacity issue with Miami being offline, given they are based there as you say.
I've been in management in corporations long enough to tell you, booking ratio and profit always pay into decisions. Meaning it's easier to cancel in advance a cruise running at a loss or near than it would be to cancel a fully booked ship.