It isn't but damn do we need to enforce it with violence that you're not supposed to stand outside the stadium?

Furthermore... Couldn't it be? Local taxpayers literally build these stadiums.

The Commons are a right. Doesn't matter that capitalists have attempted to do away with public property, by replacing it with private property, by illegally "purchasing" public property and natural resource rights for trillionths of pennies on the dollar, that's theft. Private property shouldn't exist without extreme regulations. Only public and personal property should exist with minimal regulations.