I've done guarantee rooms a couple of time. We normally only do them on Oasis class. I have a neighborhood balcony guarantee booked for Oasis in April 21. My rule is if it over $200 less for guarantee, I go with that. Especially on the Oasis class when there really isn't a terrible ocean view balcony room. Once they assign your room, you also have the option to move any another room in the same category if available.