People use it for lunch, reading, hanging out without reservations all the time. If you need the whole pavillion or most of it, better make reservations.
You have to reserve it. But if you get there and it is not reserved for the day or time it is first come first serve
You have to reserve it, if you get in it and someone has it reserved you will be asked to leave. We have been there before
Pretty sure you have to reserve it as I have seen reserved signs on it before.
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