I completely agree that drunk, violent and aggressive behaviour can and should be removed (but this can be dealt with under other areas of the law). If the plane is tech or there is a security incident, then that seems pretty obvious.
But the CoC is cloudy area.
How do you know if the CoC are enforceable terms and not unfair terms?
How do you know if a court would decide the terms had been breached?
You don't.
So in minor cases, would it not be wiser the carry the pax and then seek redress against the pax in court after the event?