However, if they are going on a cruise with you in the future, you can book a cabin in your name and another cabin in your wife's name. Your cabin would have someone else with you, and your wife would have your daughter in her cabin. You just change the name in the cabins at the pier on the day of the cruise.
Sonny, I'm not following what you're saying. If their daughter is going with them on a cruise, the daughter can just book her own cabin for a future cruise and get the onboard credit. Why the old switcheroo?