The Latin expression "de facto" means "according to the fact" and refers to a situation as it actually is, regardless of what the law specifies. It is most commonly used with respect to defacto marriages in which couples are living together in a long term committed relationship but are not actually married. I would like to suggest that teachers are defacto parents for our children.
Children spend a lot of time at school under the supervision of teachers, but a significant chunk of that school day does not involve academic instruction. Even while students are receiving formal lessons they are still being managed or babysat. Children are babysat in the playground before school and during the lunch and recess breaks. They may need to be babysat if their classmates are participating in a paid dance lesson by a visiting teacher, for example, and they have not paid, and must therefore sit in the hall and watch, and do worksheets. When the music van arrives to entertain and inform the children, as well as sell them music lessons, the class teacher has nothing to do but babysit. In class, during Crunch 'n' Sip time, children deliver their news to their classmates while they eat fruit, and either listen or don't listen, quietly. The teacher is babysitting.
Teachers don't just teach and schools don't just provide academic training for our children. We send them to school to be taught and to be looked after so that we don't have to teach them or babysit them all day. To be fair to parents, there are many things we can't teach them, either because we lack the knowledge or are devoid of the necessary skills and temperament to teach effectively. We love our children but do we really want to spend all day with them, every day? We've got our own interests and pursuits: work or leisure. So we need free babysitting, and as a bonus, our children actually learn a huge amount about a whole lot of stuff.
They not only gain knowledge and skills but also values, and it is this last area of acquisition which is by far the most important. Those universally accepted values which we are required to not only know but to practice, and which transform us into loving, caring and respectful citizens, are either taught or reinforced at school. Do we want teachers imparting values to our children? Do we trust them? Do we even care? As long as they are being babysat, as long as they are safe and happy, does it really matter what else happens at school? What is a parent? What is a teacher?