Ah thanks.I remember a few of those! Thankfully I think things have moved on in most schools a bit since then! The children at my school are encouraged to find their own voice and enjoy the fact that we are all different.I'm a prime example of this for them (I was once described by two men at a folk club as a tenor!). I don't have a choir because as far as we are concerned we can all sing and we don't believe in valuing one type of voice over another.
Instead we have a singing club which is open to everyone and we sing songs suggested by the children. We also have a "Singing stop" in a quiet corner of the playground where children can go just to sing together.