I told my wife the other day that there's no way I'd set foot on a cruise ship without bringing food and water with me. And anything else I think I'd need for that duration underway.

To ask a stupid question (maybe not so stupid since I actually served in the Navy onboard a Navy ship and spent a fair amount of time at sea) - couldn't they just use the bathroom over the side?

(not to say that any member of the US Navy has ever performed such an action <snickering>)