Technically, they will only let those that have a VIP logo on there boarding pass go into the VIP boarding area. They only way for them to get a VIP logo would be to be Platinum or be booked in a suite category cabin. The only OTHER way to be VIP is to be linked to the VIP sign and sail account for payment.
Sometimes they will let a non VIP person sailing with a VIP booking go through the VIP check but not often. The reason is that if they are not VIP, their sign and sail cards will NOT be in the VIP check in area and the VIP check in agent would ahve to go out to the general boarding area to collect their cards and it slows down everyone in the VIP line. However, some ports print out the S&S cards at the checking counter. If that is the case, then the above is a non issue and they are more likely to just let them go into the VIP area with you. Miami is one of the ports that can print the cards out. But in ports where they don't print them then its less likely you can go together. Ask when you get there but don't be upset if you are told "no".. the agent is just doing their job.
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