I have been there several times and most of the time the gate to exit is just open. I assume they have specific hours, but I haven't researched them. Also, the times I have visited and the gate was down it opened when I put the ticket back in and didn't request money. Perhaps because it was before the supercharger opened and I wasn't in there very long, another thing that could be researched to find out how long you can be inside w/o charge.