I can answer that one Simon.
The web booking is a superb convenience to us all. It was never defined as the defacto method of entry.
So when 82 are booked in it doesn't prevent people entering by other methods such as turning up on the day.
Perhaps we should place a restriction but the BFTA has an unwritten rule that anyone who wants to can shoot albeit not in the session they choose if they turn up on the day.