Belgium here... teacher... we've had decades of people suing schools for not passing their kids. The government has formal requirements, if the school demanded a bit more than that, they contested the exam results. Too difficult! Also, the school had to prove that it acted professional and gave the kid all the support it needed. A lot of work for us, little work for parents. The system was abused a lot Actually, there was a lawyer's office close to my school that advertised that they could get any kid to pass.
That changed a few years ago. These days, schools can go beyond the minimum requirements, within reason. When sued, it now is the parents' job to prove that the school did not do its job. That is a lot less work for us and a lot more for parents. It works. My school upped the difficulty again for kids age 12-14. More leave the school at 13 to follow classes in a more technical oriented school. This is the first year that all my students age 14-15 are reasonably capable of passing to the next level. (My school prepares for college). I am actually getting hopeful again.
It is sad though. Most parents are very reasonable people. They trust us, they discuss and try to convince us of our wrong the normal way. Only a small percentage of parents sued. Often it were the ... oversized ego parents ... that did that. "You mean my kid is of average intelligence? What an insult!" The whole system was bent to meet their demands. So wrong...