You misunderstand you can drink at a cafe/bar's outdoor patio anywhere in the US.

The places I was talking about in my original comment are called DORA - "Designated Outdoor Drinking Area" and usually span the whole downtown of a city. Those have cheap, but reusable plastic cups that you can get refilled at any business downtown.

Really great for festivals where you just pop in for a refill and head back out to keep watching a stage show or whatever. It cuts down on waste over cans/bottles too.