OK, this may be a silly question, but how do you work out payment for sharing a cruise? I mean lets say I agree to share a cruise with the "Smith" family on a certain date. How are they guaranteed that I am going to show up the night of the cruise? (I might be quite a shady character, you know!

)No, but really, if I pay them the night of the cruise what happens if say someone gets sick, or we can't make it for some other reason? Or what if we paid ahead of time and the "Smiths" cancel the cruise? I am not doubting the integrity of anyone, I am just wondering how everyone works these things out.