Too much money in alcohol to ban it. Due to the behaviour of people on planes now, some airline have temporarily stopped serving it but passengers could still get it at a bar at the airport or buy a bottle of alcohol at a duty free store and drink themselves stupid before boarding the plane.

I dont think they can easily ban that.

edit:// OP clarified this was meant for sports games.

Alcohol makes money, outside weapons don’t. If they could get away with selling you knives in the stadium they probably would.