HotelTonights namesake feature is also holding it back: You can only book a room beginning at 9AM on the day of check-in. If youre planning to arrive during a major event, say, in Los Angeles during E3 or Rio during Carnival, landing without a confirmed room can add to the already stressful travel process. But the folks at HotelTonight have a good idea of whether or not youll be able to find a room, and the teams now ready to share that info with you.