Fencing unfortunately. However, at the entrance, make it a one-time fee (at a debit/credit kiosk) that is refundable after a day or two. Maybe $3-$5 per entrance — that would keep those out who don’t have a credit card available or wish to be known they were there.
A small camera could snap a one-time pic at each entrance or transaction for added assurance/recognition. You’d then have names per each entrance, proof they were there, etc., with a picture.
Added bonus: A stolen CC would then have a pic of the scammer in action! Sad we have to incorporate restrictions such as this for those just wanting to spend time with their kids. Until this country turns around, it will only get worse. Just my two cents.
SHANE LaCROSSE
Yakima