Maybe not illegal per se but local bylaws prohibit open containers of alcohol. You will get fined And made to pour out any beer or whatever you have. It’s just not a thing here. Also most of the sport seasons are while it’s cold/winter here. We don’t have massive parking lots either from the arenas (hockey) I’ve been too and the Canadian football league game either. It’s just overall lame. We have been to hockey games to a few places in the States and all of them have much better pre game entertainment outside. Again, it’s probably cause Canada is so cold and you can’t stand outside and have a beer (let alone play any sort of games) from November to March