Stolen from another WDW news site:
Disney Cruise Line is instituting a new procedure for gratuities on all their ships. On embarkation day, guests' folios will automatically be charged for the suggested gratuity amounts for Server, Assistant Server, Head Server and Stateroom Host/Hostess. Guests can still add pre-paid gratuities at the time of booking or when making their final payments. If this isn't done, a letter will be given at check-in explaining the automatic gratuity payments. Modifications to the amount can still be made at the Guest Services Desk.