A friend of mine is a keen facebook messager. She leaves messages on facebook about every aspect of her life. This includes events at school, good and bad. Her messages regarding the school are not about individual people, but about the school system or how it is run.
In recent weeks she has added 3 separate messages on facebook about the school. Firstly, the hours they have given her children at nursery. Secondly, the way the school disciplined one of her children when they were naughty. Thirdly, the way a teacher had shoved one of her children over when disciplining another one of her children. Her children are 3, 4, and 5 year old twins.
Yesterday, the head of the school asked her to stop adding any messages to facebook about what happens at the school. My opinion on this is that, as long as it isn't personal about an individual, messaging about the school is part of freedom of expression.