What generally happens with a roll away is they will bring it in right before they come to do turn down for the night.(while ur at dinner) and then in the morning they will remove it to maximize the space you have. Then rinse and repeat the next night. lol
Now if for some reason everybody wants to take a nap or you just want the RAB there, you can call the room steward ext from the room phone and you will get it delivered.
Now I have read other places, Never had it happen for myself, but ive heard sometimes they squeeze it under the king bed for storage. Now to me thats a tight space but thats been in some reviews over the years.
Hope that helps a tad. Bon Voyage!!