Call them; it will be specific to the event.
They sell some drinks at the venue, but you can't bring in anything from outside
Depends on what you're attending. During concerts, you can buy alcohol to take into the theater. Food can be purchased, not sure it can be taken in. Nothing can be taken into the art museum.
I didn't see anybody with anything that was during a high school graduation. Also I didn't see any concessions. I would imagine you could bring in water.
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