Did I get this correct? The $100 NCLH stock OBC is NON-refundable, and the $50 shore excursion credit is refundable. Thus if you book on board a $100 excursion it will be taken from the non-refundable account. Thus at end of cruise you would have refundable $50 shore excursion which would be money refunded to you. Sounds confusing, but neat trick if true!