Absolutely, Carnival is very proactive. They also waived all fees for the phone and wifi on the cruise ships that are kept at sea (I believe most cruise lines do that though but it's reassuring to know that Carnival does it too) so they can rearrange plans and be in touch with family.
John Heald is also wonderful when it comes to keep people informed about what is going on. Also on the website they always inform you in advance when the next news are going to be.
Last year, we were sailing right after hurricane Matthew. It was a bit stressful because the day before our sailing, we had to fly in Orlando without even knowing if our cruise would happen at all --but, it's nothing compared to the stress the locals have been going through, of course!--, when I called, Carnival recommended that we fly anyway... and we learned at 7:00 p.m. the day before the cruise that we were actually sailing the next day but we would have an overnight in Nassau instead of going to Freeport.
Not only the news were posted on the website but John Heald posted them as well (an made many videos talking about it) and we received official letters by e-mail as well. All that time we had that "they got our back" feeling.
I have to say that sailing in hurricane season made me more resilient about travel plans as I don't take original plans for granted anymore and keep my mind open about change and non-planned port of calls.