The school I want my DD to attend has this as part of their admission policy in relation to siblings. It is a church school and places are awarded on the basis of attendance at church of a parent and the child. Priority is given to looked after children. Then siblings and then done by church attendance and distance if there are too many applications.
They award points for how often the parent and child attend. Surely the statement below should also mention the church attendance of the child sibling to be admitted and not just of the parent.
"The Governors will give priority to applications from brothers and sisters where their brother or sister will still be at the school at the time of admission, provided that the faith commitment of the parent is evidenced as outlined above and has been maintained since the original application for entry for that sibling into Year 11 or below. This priority applies equally to step-brothers, step-sisters, half-brothers, half-sisters and adopted brothers and sisters living at the same address."