Block bookings

I have been trying to get a weekend at Baltic Wharf for years and it is permanently booked.  I suppose this is due to those who block book sites when they are released but how many of those book a pitch just in case?  I would be really interested to see the cancellation statistics for some of the most booked sites.  Maybe the Club's policy needs to be reviewed or failing that set up a cancellation system so that those who want to visit a particular site can register their interest?