If you are leaving site earlier than planned

If you are leaving site earlier than planned, please inform the warden. The Club will retain one night's fee as it is very difficult to resell the pitch at such short notice;

I have copied the above from the rules and I know that I am going over old ground but a thought has occured to me. The club will take one nights fee which could be on average, pitch and 2 adults  or it could be a family, surely a fine of pitch and one adult would be fairer.