As posted on the Coral Princess's web site:
If traveling via Cancun, Coral Princess H & R will refund the transportation cost from Cancun to Cozumel (Bus and Ferry only, one way). Refund will apply in Food and Beverage consumptions, 3 Nights minimum stay, all room types.
Promotion applies only for transportation of adults and transportation tickets (Bus & Ferry) must be presented upon check-in. Non refundable for consumptions not made, no cash value not valid for phone calls, laundry, etc. Not apply with other F&B promotions or Meal Plan Option. Valid from Sept. 25th, 2008 trough Dec.19, 2009.
Makes doing the bag drag a bit more bearable.