I agree with Andrew.
As an example, on Thursday of this week the caravan club website said there were no pitches at my local site - Clumber Park.
Tonight there are 13 pitches showing available for the weekend. These are either people that have cancelled on Friday or no shows.
Whilst I accept that there will always be instances where cancellations have to be made - eg illness, weather, work etc I cannot for one minute believe that 13 caravanners local to Clumber Park were taken ill overnight on Thursday.
The caravan club know who these people are, but seem totally disinterested in doing anything about it.