Sorry, no sharing at buffets. If you're there they will charge you. I took my GD to Akershus a few years ago. She didn't like anything on the menu and literally ate only a couple bites of dessert. We got charged for her. Even the waitress said it was a shame she had to charge us, because she saw my GD didn't eat anything, but then she laughed and said, "of course, it's the characters you're paying for." On the same trip my GD also didn't eat anything, but a couple bites of fruit at CRT. Again we got charged for her. The year before that, I got too hot at MK and got ill. I still went with my son and GD to Crystal Palace, because I really wanted to see my GD with the characters. I literally did not eat a bite. The waiter did bring me some ice tea and that's all I could handle. I was still charged, just as if I had eaten.
Liberty Tree Tavern used to have just an entertainment fee you could pay if you weren't going to eat, but they've done away with that. If you go to an all you can eat restaurant now, you pay.