It is up to the host family to discuss with the Shinshinim who will be making lunches. If your kids make their own lunches, feel free to let the Shinshin make their own lunch, provided you are supplying them with food. Make sure they feel comfortable making it. Again, treat the Shinshinim the same as your own children. If a parent or a housekeeper makes lunches for your children, have them do the same for the ShinShin.