Unfair treatment of a caravanner

Easy enough to close grass pitches over the winter and wait for better weather before opening them but what do you do when you have a wet spell in the summer months and a site is fully or near fully booked?

 If really bad, wardens could phone the last to book up and advise them not to come, but if it is marginal it makes sense to let the wardens manage pitch allocation. I have experience both occurances in summer.

peedee