The park closes at 8pm. If you didn't return from a long walk down the beach til 9pm or so will you be locked in the gate or have to pay a fee?

There is a gate there.

I'm not sure. I went early and left before noon. I don't remember seeing a gate but there could've been one.

I do not remember seeing a gate when I visited 2 weeks ago

Definitely will be locked in

Locked in