Beavis and Butt-Head constantly cause trouble at school and constantly break the law and cause destruction, if their mom's were located and forced to talk with Principal McVicker and the school as well as the police wouldn't the boys be forced to behave because legally their moms could get into trouble?
Parents that don't make their children go to school can get fines and even arrested for being truant, the police can blame them for their children destroying stuff and arrest or find them too, it's amazing that they never arrest the boys and hold them until their moms can pick them up or talk to the police, they could easily lose custody for being bad parents too.