Liz,
That is a completely ridiculous way to treat a child and I hope you didn’t do this to your grandchildren. Remember, they are children, not animals. Nutritionists will inform you that a child needs to be offered a variety of foods at each meal. This does not mean that you have to be a short order cook. They either eat what is there or they do not, but they do need a variety. Also, it takes a child 20 times to try a certain food before they decide they like it or not. The 2 year old is still trying to figure out what he likes. Also, a 30 minute rule is okay. I personally think it is disrespecting your child. How would you like to go to a restaurant and have a server take your plate away after 30 minutes? However, children’s appetites change from day to day and if they are not eating what you put out within the 30 minutes, most likely the portion sizes are too large for the child.