I ordered appetizer as entree when I was on DDP(regular) this past xmas with no problem. If it is used as your entree, (did this at Kouzzina, Sci-FI can't remember other)they actually make out $$ in most cases. If the appetizer is for 2 then I would guess you would need to use it as entree for both of you.
Thanks I was just talking about KONA, but from what I hear Kona Island does accept DDP but its a TS credit. Atleast thats the experince a few ppl have reported here..