Clemson,
The problem with having paid attendance only is that there are some legitimate free days or promotions such as a free adult with child day or a free gate promotion. Consequently, the fair must estimate those people who have definitely come to the fair and are part of the attendance.
There is a problem that it is not an apples to apples comparison but we are trying to get at a legitimate "total attendance" number. "Paid attendance" only may not reflect this number accurately. In the case of a free fair like Salem, Va or Ionia, MI which has previously been on fairs lists, it is very difficult to gauge attendance and we considered and will possibly consider again, leaving them off with out any additional information to strengthen the veracity of these numbers.
Thanks for the comments.