The Ambassador Program you may be remembering Denise is the Ambassadors of the Environment that is related to the Paul Gauguin. It is a program to involve children in experiences with nature and the ocean. Nothing to do with a referral bonus for new guests. Same name may be confusing the two issues.
The only referral bonus to a past guest for referring a new guest I have ever heard about was related to the Presidents cruise as mentioned by Tallship.