well the best and simplest solution here is to offer both. That way those that like talking with a LIVE person can do so and those that capable and willing to us a kiosk if it means not having to wait so long to board can do so also.
Like Cruise Fanatic said... most of the chore is already done when you complete the online pre-registration. Of course it will still require a real person to stand there and help with issues like they have at the airlines now, but they can have a bunch more self serve kiosks to one real person and speed up things for everyone.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013