This is not always true. If you find there are no rooms available it does not necessarily mean someone sitting next to a screen beat you to the reservation. I recently could not get a reservation on what should have been the first date the reservation was available and was told those rooms would not be available for two weeks and that the hotel took care of the bookings themselves, giving preference to Plat awards members. Call the hotel directly and ask them your questions because the answer I've learned can differ from hotel to hotel. For example, if you think the general rule is rooms should be available on the 12th but it turns out it is the 19th you might miss your opportunity.