Not sure if I'm allowed to post the link, but here is the link to the language for Celebrity:
http://www.celebritycruises.com/plan-and-book/before-you-go-future-cruises?tab=before_you_go_future_cruises/plan-and-book/before-you-go-future-cruises?subtab=true
The language for the rccl certificate -
"NextCruise Confirmed Booking: Select your ship and sail date at the time of booking. A $50 to $500 non-refundable deposit per person is required to partake in the Next Cruise program when booking 5+ night voyages. The deposit schedule is the same as the Onboard Credit Schedule and is determined by category of stateroom and length of voyage. Reservations may be cancelled but deposit would be forfeited as it is non-refundable. Reservations may be changed to another ship or sail date up to 90 days prior to Holiday sailings and 75 days for all other sailings. Changes to reservations are applicable primarily to US, Canadian, United Kingdom, Ireland, European & Australian guests. Not all countries follow this cancellation/change policy. Onboard credit has no cash value, is not redeemable for cash and will expire if not used by 10:00PM on the final night of the cruise. Next Cruise offers are not combinable with the following rates: Interline, Travel Agent, Travel Agent Friends and Family, weekly Sales Events, Net Rates or Shareholder Benefits. They are combinable with Crown & Anchor Balcony and Suite discounts and Savings Certificates. We value our relationships with our Travel Partners and unless we are advised ahead of time, your Decide Now confirmed booking will be attributed to the Travel Partner associated with your current cruise booking. However if you wish to have your booking reflect an alternative arrangement, please advise at the time of booking and a form will be provided for you to sign as authorization. Amount of Instant Onboard Credit ranges from $50 - $500 per stateroom and is determined based on category of stateroom and length of voyage (minimum 5 night sailing). Maximum one Instant Onboard Credit per stateroom is to be applied to the current cruise. Once deposit/Instant Onboard Credit is locked in, that will fulfill the Deposit / Instant Onboard Credit for the current cruise. Once the deposit / Instant Onboard Credit is applied, the only remaining benefit is the limited time combinable North American offer at the time of booking (excluding China product). You may change your ship or sail date, but your onboard credit is subject to repayment out of your onboard deposit if you book a lower category or shorter sailing. Program applicable to new individual Royal Caribbean bookings made after March 6, 2015. Bookings may be transferred into non-contracted groups and full deposit may be required. Individual enrollment may be converted and applied to a group booking. International deposits and requirements may vary. Please see your Cruise Sales Team for details and deposit policies. For those guests that choose to have their Onboard Credit on their future voyage, if the original ship and sail date selected while onboard is changed in the future, we reserve the right to adjust the onboard credit amount to the Open Booking model between $25 - $100 per stateroom based on length of cruise. After the Offer Period for any North American Offer that is combinable with your Next Cruise Booking has expired, the Offer will be removed from the booking if the guest cancels and reinstates the booking, applies a fare change, or changes the ship or sail date of the booking; certain other changes to the booking may also result in removal of the Offer. Additional deposits may be required for Grand Suites and above. At least one name must remain the same on the booking. Offer is subject to change without notice, capacity controlled, and may be withdrawn at any time. Royal Caribbean International reserves the right to correct any errors, inaccuracies or omissions and to change or update fares, fees and surcharges at any time without prior notice. © 2015 Royal Caribbean Cruises Ltd. Ships registry: The Bahamas."