So, they have a permit to close off the area and charge you to enter their special area of the public thoroughfare?
(looks like you need to buy a $25-$45 ticket to get in)
And they're treating that public right of way as their private territory during this limited time event...
I'm thinking I'm not qualified to have an opinion on the legality of it all, but it is Grand Flipping Rapids, so regardless of the legality, the city will side against us in any dispute.
https://foundersbrewing.com/taproom-events/founders-fest-2019-a-celebration-of-beer-and-music/What can’t I bring into the event?
No outside food or beverage
No glass or growlers of any kind
Empty (non-glass) containers for water or sealed bottles of water are OK
No pets (licensed service dogs OK)
No fireworks
No illegal substances
No weapons
No bad attitudes
No flagpoles
No totems
No chairs on city streets