They should give out tickets on free days. Give or mail them out more than a week in advance. Either use tickets or keep the numbers down, have a numbered sign posted with the amount of people admitted thus far. Or, just revoke the tax and give people that 1/8th of a cent back in their pockets.
“Give or mail them out more than a week in advance.”
And I would do it only if requested by the person. Single mom struggling to keep would plan ahead to take her kids to the zoo and enjoy a nice day out. Gang bangers - not so much.