It’s typical w/events like that. Every year during Memorial Day weekend they have “Black Biker Weekend” in Myrtle Beach, SC. Crime is sooo bad that businesses close up that weekend. They cried racism but it’s nothing but a giant thug party. I would close my business too. When they get into large crowds like that, it’s anything but civil.
I’d close up, board up the windows pre-emptively, and sit on the roof with a scattergun.