I had the misfortune of having to school my daughter with several kids whose parents just would not treat their lice. After six months of re-infestations, my daughter came home crying, saying she wouldn't sit next to this one boy anymore because there were lice dripping off his head. She found them in her socks at school!
We went through hundreds of dollars and a lot of stress in treatments. I had to cut her beautiful long pretty hair short...
All because I couldn't afford to move areas, and these few families had the LEGAL right to refuse to treat thier kids. The school could only advise and send them home when the lice were visible.
I felt for bad the ever-infested kids - and I definitely see non-treatment as child abuse - but I was so, so angry with their parents and the legislation that means the "nit bus" doesn't come by once a year and dose ALL the kids at once any more, like it did when I was in grade school.
Anyway, we all have louse-trauma after three years at that school, itching and dosing and itching and dosing, it's embarrassing and uncomfortable for everybody, not just the kids who aren't being treated.