I was there last october when my DD was 2 and a half. My DS(6) and I had the dining, but b/c of DDs age, she was supposed to share off my plate. One night at dinner, she wanted a personal pizza like DS -- we go her one, and they just took 2 credits off my son's plan. The waiter said that was ok -- to quote: "they're your meal credits, you can use them however you like".
There are rules though, I'd guess it would really depend on how gracious the case member is. Good luck!!