Concert etiquette: what about children?

Our latest event, Bearfoot in concert, was a rousing success! Many people have called or stopped by to say how much they they enjoyed the band, the music, and the whole event.
Some folks left comment cards, or stopped at intermission to ask that we do something about the unsupervised and noisy children at the event. This is a tricky issue:
1) We deliberately invited young people by having cheap tickets for them, and by reducing our general ticket price significantly to encourage families to come. Siblings probably participated in the camp that the band held prior to the concert, and the whole family no doubt wanted to come to hear the music.
2) We like to encourage young people to become patrons of the arts by making events and concerts that they can appreciate and enjoy.
On the other hand, part of becoming a patron of the arts is learning to treat the arts respectfully: Just as you don't touch the paintings in the gallery, so you don't touch the music that another person is making by making your own sounds while it is happening. So you learn to listen, and look, and pay attention. Hard for a little one!
So what is the best way to handle this? How do we, as the arts council hoping to create an experience that all our concert-goers enjoy, help the very youngest among us refrain from interfering with the enjoyment of the older more serious aficionados? Do we ask the parents to speak to the children? Do we talk at the beginning to the children and remind them about sitting and listening carefully? Do we make it clear that this is a "family event" and family sorts of the noisy restless variety may attend? What is a good approach?
Nancy