I know that some parents feel that their children can be a light in the public school system, and use the opportunity to witness to others.  Does this happen at times?  Yes, I'm sure it probably does.  Is it scriptural?  I don't see it in scripture.  For a child to "be salt" to the world around them, they need to first become salt.  This time at home, when a child is young, is a time of training - of growing in their Christian faith.  The onslaught of darkness in the public school system is overwhelming to a child, and not what God intends for the young.

My sister and brother-in-law work in the field of addiction recovery.  One thing they try to help the clients understand is the pull on their lives of wrong influences.  They have an exercise where they have one person stand in the center of a group of two or three who are sitting.  Can the one person pull the three up, or will the three who are sitting be able to pull the one who is standing, down?  What do you think?  Of course, the three sitting will be able to pull the one who is standing down.  And that is exactly how it was when I was in public school.  The Christians I was in public school with failed miserably - and so did I.  Temptation was great, peer pressure was great, and the onslaught was overwhelming.  I can promise you, I was not salt.  None of my Christian friends were salt.  None.  Zero.

Matt. 5:13  Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men.

When Jesus sent out his own, he had specific instruction.  They also had a time of intensive training, where they not only learned by way of lecture (as in the Sermon on the Mount, etc.), but also by individual attention, and special "disciple" training.  They also saw signs and miracles.  They faced demonic activity, disease, and a worldly attitude.  They were sent out by twos.  It was no small thing.

Try and imagine them as children, ripped away from their parents at 4 or 5, and an indoctrination being enforced upon their minds.  It is not what God intended for these children.  These are to be witnesses - lights - salt?

Home where they belong, we can give them that intensive training.  They can see Mom and Dad's faith in action, which will at times include making mistakes and crawling out of a pit by the grace of God.  Nevertheless, they will see God at work, and they will become salt.  Home where they belong, they can learn God's Word, and be strengthened - reinforced if you will - in truth.  Let's give them the opportunity to grow in the grace of our Lord, Jesus - home where they belong.