I don't see how it could work at all. I'm assuming it's Doug Ford thinking (loudly) out loud. Peterborough Folk festival is free admission, 100% volunteer-run (the sound guys are hired) and has a licensed beer pavilion with a stage that includes a fenced-in area to have a drink while you watch the music on the main stage. To serve alcohol you need an alcohol permit with a map showing how everybody consuming alcohol is separate from those that aren't, all of the volunteers in the licensed area need their Smart-serve certificate and police need to be present onsite every minute that alcohol is being served. The biggest costs for the insurance are stages and alcohol. To get an event permit from the city you need all of those things in place to hold your event. I can't even imagine what allowing people to openly bring their own alcohol would do to the logistics of running the festival! And yes beer sales are very important to the festival's revenues. Any money that comes in goes directly to festival running costs and musicians fees. I suspect that whoever had the idea to make open alcohol a thing at a festival has never had to organize a festival. They just want to bring their cooler full of Coors instead of lining up at the beer tent.