No promotions for moving people around.
Hubby and I both receive occasional casino offers. When we booked this cruise, his offer was for a 'free' cabin (plus a fee, plus port fees, etc. Plus the price to upgrade if he wanted anything other than a random interior cabin. So not free but a deep discount off the sticker price.) My offer was for a Drinks On Us! card and an onboard credit. We initially booked two cabins for four people, him and his dad in one and me and son in the other.
When son's GF's parents agreed she could join us, neither promotion we booked under was still active. It would have cost a LOT more if hubby had cancelled his reservation to change to a 3 person cabin. I only lost my drink card and onboard credit, so we cancelled my reservation and rebooked the 3 person cabin in my name.
There were no promotions for moving people around. I was concerned that moving people around would jeopardize the promotions we are booked under.
Hope that clears things up some. 🙂