my friend was given a $100 GC & ice cream - BUT she was staying on my points, at the BWVs (part of her college grad/bd gift from us). she wound up buying DVC herself (AKV). when she went back with a friend last year (stayed at AKV), the friend was given a $100 GC (& ice cream) for attending.
incentive is usually higher if staying DVC on someone else's points, otherwise, it is usually FPs and ice cream