What to do in this situation?

This past weekend I was invited to a yacht birthday party of an acquaintance and she allowed me to bring couple guests, whom she had never met. The yacht party was open bar and everyone got drunk. One of my friends apparently threw up on the boat and now she is saying she has a cleaning fee and wants us to pay. I'm not sure what to do in this situation. I asked her how much the fee is for the cleaning and what she is asking monetarily. A friend told me she is getting a charge of about $800 which is outrageous to me. Part of me feels like I would be willing to tell my friend to help out with the cleaning as long as it's reasonable, BUT at the same time, if you plan on having an open bar yacht party you should know the risks ociated with that and know that people may throw up and that's a responsibility you should be aware of. It's like throwing a party at your house, or driving your drunk friends home.........are you going to charge people for cleaning? Isn't that a responsiblity that you take on unless people break something I understand. Also, we never signed anything when boarding the boat stating that we are responsible for an outrageous charge if this happened. If we signed something or informed prior than it may have made a difference. I don't really know this birthday person and she was very rude to me the whole time I was on the boat as her guest so I'm also not inclined to be nice and to compensate her. She said my friends should know their limits while she was carried out off the boat. I am just conflicted what to do.......does she have any legal recourse if I say no to paying up?