Out of interest - what would happen if the holding charges 'used up' the available balance on a passenger's credit card, so that there isn't enough available when Cunard then claim the full amount at the end of the cruise?
So - using random numbers as an example! - let's say a passenger is using a credit card with an available balance of 2,500. They spend 2,000 on board - all of which is 'held'. They would then have only 500 available balance 'left' when Cunard try to claim the full 2000 balance. What would happen? Assuming, for the sake of the hypothetical scenario, that the passenger does not have access to another credit/debit card or cash...?