I was one who said that I could see myself using this punishment. This girl is going on vacation soon. The parents can't take away that vacation, that would punish the family, too. All they can do is say that she can't take her friend. That's probably a big deal. Sure, this probably won't fix the "refusing to clean up her room" bit, but probably the biggest issue here is the disobedience and probably the brattiness that goes along with it. I am sure the parents don't really care that much about the clean room. They are just trying to raise their daughter right. And even if it won't fix it, you at least have to try, right? You can't just throw up your hands and say..ok, my kid's going to be a brat. Oh well.
And as for the jet ski thing..my kids aren't even teenagers yet and I could see my oldest agreeing with that punishment. Oh, ok, I can refuse to clean my room and all that happens is I don't get to rent jet skis? That's no big deal at all!