I did it once and will never do it again. Some of my wise friends said to me, 'Does it cost you less to feed one of the children? Are the crafts shared or do you have to pay for both?' They told me if I ever have a parent ask for a sibling discount again to ask the parents which one of their children they would like me to feed and teach because they are not paying me to feed and give crafts to the other one. Wise words.