Jeez, they just can't catch a break down there.
Not quite as altruistic as Carnival donating one of their liners for use as a barracks for relief workers after Katrina. But whatever the justification, the thought of letting vacationers disembark for some R&R in a city destroyed by an earthquake is a little revolting.
Why not coordinate with relief agencies and find a few nonskilled relief activities where help is in short supply? I heard it's taking forever to unload supplies off of incoming airplanes, stuff like that. Explain to the passengers that due to the obvious catastrophe, we're only here to unload supplies. But if you would like to give an afternoon of your time to help the Haitians in their time of need, you can disembark to help with A,B, or C. If the local vendors are anxious for business, let them set up shop at the pier where the ferry comes in. Wouldn't that be a kind of win/win situation for everyone? Or is there something about it that's not practical?
EDIT: Just read the bottom couple paragraphs about the port of call being some distance away from Port-au-Prince. Does that completely torpedo this idea?