Why not stop them boarding
I am all for offloading abusive and violent passengers, and I think that there should be a zero tolerance policy -- an airplane is not a place like a bar where you can throw people out later. At the same time I also think it is unfair to delay everyone else. Isn't the obvious solution just to be more careful at the gate and leave the drunks on the ground?
Just two weeks ago at CDG I saw two very obvious drunks staggering around the gate area pestering other passengers. I was amazed to see one of them again on the plane trying to move into business class and being dealt with very effectively by an AF hostie.
I agree that there will always be some pyschopaths that don't appear drunk but still misbehave, but surely a no drunks policy would reduce the risk.
And if that is not possible could they not put some sort of cage in the pointy bit at the back of the plane to accomodate these people?