That's because you need two more things besides just a pre-nup: A POST-nup and $15k to the woman to go find her own lawyer to work through the paperwork so she can't claim ignorance. With that you are pretty safe.
As an aside, I know a guy who had his father own the deed to his house and paid "rent" to him. When the wife cheated on him and left/was kicked out she couldn't get much because most of his assets were in his dad's name.
Other than the possibility where that could be interpreted as not trusting your partner, that sounds like a great idea from a "CYA" perspective.
Of course, it could only really work if the relationship you have with your father is very solid. You wouldn't want him kicking you out of "your" house because of some arbitrary conflict.
