FlyerJ is correct in his post and this has been discussed at great length in other threads. Although it does seem they are lying, it's more likely you're dealing with faulty data. What properties load into SPG.com typically does not represent actual inventory. Hotels have been in the business for quite some time and there is a ton of statistics that support the over-sell technique. In the case where everyone does show up, the property will exercise its walk procedures. And should they have a walkup, rack rate gives them lots of wiggle room in putting people elsewhere as they may have cooperative agreements with nearby properties to take their overflow if possible.