Two other reasons I can think of to crown cap a swing top bottle in commercial brewing is tamper proofness and machinery. Simple machines put in crown caps but it takes a person to latch a swing cap. I use the standard bottle capper with the two handles that swing up and no base so it caps anything. You can fill a bottle from the keg and cap it for “legal” transport. Swing tops are considered “open containers” like a screw on lid for a whiskey bottle.