There is just so much wrong with this. Everyone who paid money for this entered into a binding contract with the promoter, and in that contract it gave the % that would be refunded if "YOU, the individual cancelled. Now according to contract law(got this from a lawyer friend of mine) if you as a promoter cancel a show, tour, cruise, then you the promoter are responsible for refunding "EVERYONE'S MONEY IN FULL", not just a portion Talking about someone loosing credibility.
Here is a statement from the official cancellation press release from blabbermouth:
"All tickets purchased may be honored to cruise on the Carnival Imagination without the event and a partial refund will be credited to those exercising this option. Purchasers who would prefer a full refund will receive 100% of their purchase paid."