Originally Posted by Jon Baker

The CoC doesn't mention permanent refusal of carriage, just refusal of carriage (which reasonably would be taken to be related to the itinerary booked). That said it isn't explicitly specified either way, so I guess that it could be possible to argued ​​​​either way.

However an airline which permanently refused all future carriage to all passengers who dropped legs, segments or returns would surely be cutting of its nose to spite its face.