For those asking why not - in my own experience, and after a discussion with CMs at POR, it's the CMs first priority to get you into a room that will be ready at your arrival time if you've checked in online. If they can meet your request while getting you into a room that will be ready, they will do so. In my experience at POR, I requested a mansion room but those rooms had not yet been cleaned when I arrived. Since they assigned me a room that would be ready at my arrival time, I actually got the exact opposite of my request. I politely asked to be switched and they warned me, twice actually, that the room I was switching to was not ready. I didn't mind. I will say it was a giant hassle to have me switched out of that room at the online check-in desk. Because of this experience, I probably won't do online check-in again unless I stay at a resort where I have no requests.