Yes, even minors. Anyone who has a past guest number will have a VIFP account. You don't HAVE to use it, but if you want to check the status of your childern and check to see if their cruise history is correct you will need to create a login in for them. Its a pain but really nothing different than before. You could always have created a member account for a minor past guest and use their past guest number. This account would then have shown their past cruise history.
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