I'm not sure if this is implied by the phrase "common carrier" - but does the presence of a "last lane" imply that the carrier is no longer able to claim "common carrier" status and is therefore liable for the content delivered over their infrastructure? Currently, US ISPs can claim they don't filter based on, eg, obscenity or content that may be illegal in some jurisdiction. If they give up net neutrality, can they be found liable for content?