With all their historical data, they know what rates to offer at various times and through various channels, but sometimes, by simply picking up the phone and calling the hotel, if you get the right person, you will be surprised at how low of a rate you can get.
Case in point: I recently missed a flight home one night and decided to fly home in the AM as opposed to waiting until 10PM on standby for a flight that was sold out.
First thing I did was check the Marriott website. They had numerous properties nearby, ranging in cost from 118 to 199. I searched again and clicked on AAA discounted rates. One room came down a full 90 bucks for a Springhill Suites and showed a price of 80 bucks. AAA rate for the Courtyard was 119.
I then called the Marriott reservations line, told her what I was seeing online. She checked the system and came back to me with a room at the Courtyard for 64 bucks and I booked it immediately.
Several factors in play:
I am a marriott rewards member, not sure if that affected things.
all marriotts set aside x number of rooms for AAA discounted rates, Even if you are not a AAA member, just book the rate. I have never been asked to show my AAA card.
Especially if it is same day booking, if they have a lot of inventory, they would rather sell it cheap than not at all.
Of course, if inventory is low, you will pay higher rates, even if booking well in advance.