Actually I was worried in January about this same thing. Just to be safe I called to inform them we would be arriving very late (after 1 AM) at BWV. The CM said "Yes, it is a good thing you called to let us know". I don't think that they would have given the room away, but everything was ready for us with minimal paperwork. Had to ring the bell to get the night clerk who was expecting us. Better safe than sorry-I would call and let them know.