This is the gray zone. I bought the right to sail on a certain itinerary, so money was exchanged and taxes are owed. The fact that I don't sail might not mean I'm entitled to my taxes back, especially if NCL keeps the money. IIRC, sales taxes are considered a "transaction tax," so if the cash transaction is not reversed, the taxes may still be owed. Also, I've read that the port fees per person are some type of proration over all expected passengers of port fees owed for the ship to dock. I a person fails to sail, the ship may still owe the same port fees.