Yeah pretty sucky! It is one thing to have to pay for the neighbors car/house window when your kid puts a baseball through it, it's a whole other thing to pay for your kids failure in school. ESPECIALLY after they turn 18!
You can do lots of things, but you can't force a kid to study. I'm doing that with the boy right now, and he can sit in his room for 5 hrs and accomplish nothing, if he doesn't want to do it.
I also know how fast they can disappear from school, the boy has gone missing a few times for up to 45 minutes when allowed to go to the bathroom alone.
Before school was mandatory, kids would be poor dirt farmers, but at least then, they had something they could do without an education. Pretty sad.