Never understood

My SIL will cook 3 different dinners if her kids decide they don’t want it. Like today she cooked mashed potatoes, corn, and spaghetti and her son said he wanted burgers so she cooked him a burger and her daughter said she wanted manwhich so she cooked that. She said if she cook and when it’s time to eat if they decide they don’t want it she cook what they want or they will pout and just twirl they food around the plate. I think that’s insane, if I cook and it’s food my kids eat and they decide they don’t want that well idk what to tell them. I’ll offer them veggies but no way will I be making separate dinners my geez that’s a little bananas I think. She does this on a regular cook and her children decide oh I want pizza so she get pizza and the other will want chicken nuggets so she now has 3 different dinners at her table. Her kids are 5,7. Do other parents do This also?