Reservations for popular campgrounds

Is it possible you and the booking site are not on the same time zone? I have no clue as to whether or not the reservation sites are sync'ed to the local time zones or whether they use Eastern time, greenwich mean time, or the time zone where the reservation center is located, which could be in India for all we know. I highly doubt that there are bots tied to making reservations, since most cannot be resold. I think someone has already hit upon the key issue, there just aren't that many sites available. For example, if it is a 100 site park, and the average stay is a week, that means less than 15 sites become available on an average day. Considering a popular concert can sell out a 20,000 seat venue in a matter of minutes and those seats are only being sought by people in the immediate commuting area, 15 sites in a popular national park, where there are people wanting to make reservations from all over the world, they can go away pretty quickly, especially when there isn't human interaction to jockey sites and maximize the usage of the park.