While I think lying to start any type of relationship is wrong, I think whomever David picks should stay with David, only for these two reasons; They don't want to be viewed as money hungry, and two they can ride the fame afterwards. For example, Cat wants out of Berlin? Well, stay with David till the end but than do interviews, etc and ride the 15 minutes of fame!!
If there is a suprise, it has to be about money. The women get offered it, or David really has some. But it has to relate to money or something that can be made to make money, because I can't see Fox doing anything other than. A suprise twist without money really isn't a suprise twist.