While I am not thrilled when one sibling is sick, but the other comes to me, I don't know that I would go as far as actually forcing both to stay home if one is healthy. I don't see it necessarily as the parents being lazy...it could be that they want to be able to care for the sick child better and/or take him/her to the doctor without having to drag the other child along. A sick child sometimes requires a lot of TLC and maybe the mom or dad at home just wants to be able to provide that without having to keep the other child entertained as well. If I have one sibling sick, I just watch the other like a hawk for signs of illness and hope for the best. If a parent is sick, I don't expect them to keep the kids home in case they are carrying germs. If one of my kids is sick, I don't keep my other healthy child away from the daycare kids. I just think there is only so much you can do.