Children under 3 can share from your plate at any restaurant...of course with buffets or family style meals there are more options and food to share with your child..essentially they are eating their own meal. I find these types of restaurants to be the best when travelling with a toddler.
I have brought my own food many times to different restaurants for DS. He's a pickey eater and even if I was to order from the menu for him chances are he wouldn't eat it. I bring Gerber graduate toddler meals (pasta pickups) with me for DS to eat just in case there's nothing on the menu or buffet he wants. I also bring some of his favorite snacks and I've never had any problem doing so.
I went to Akershus 2 years ago with DS..he was under 3 and not on DDP. Akershus has a hot dog on the kids meal but way overpriced to pay out of pocket. I had my trusted raviolis with me and as others have said there is an appetizer buffet. When the CM took our order he asked what DS wanted...I told him DS wasn't on the DDP and he would share. The CM insisted it was no problem and that he was "allowed" a meal ..and I re-iterated that he was not on the dining plan - they said no problem. So I ordered a hot dog kids meal for him and we were not charged for it. I'm not sure if it was a fluke or just the way they do things at Akershus, but it was a very pleasant surprise.