The embarrassment is usually rooted in the sudden adult realisation that we have been getting something completely wrong about their feelings, wishes, needs and attitudes. We have been underestimating, overestimating, assuming, or (most often) pointlessly hiding something from them which they have known about for months. If we have any grace, we blush. If not, we bluster.
But sometimes the only graceful response is an embarrassed gulp and a throwing of the hands into the air in surrender.
Nine-year-old truthteller of the month is an anonymous boy in a survey by the magazine Zero2Nineteen about students' views on school councils. A report published last week suggests that children don't think much of the consultation process, especially where expenditure is concerned.
This child says, in tones any parent can easily recognise as authentic:
"They've just bought us proper football posts and nets. They cost loads. We used to use our jumpers as goals and we were quite happy with it."
Alas, I do not know what he would have preferred the money to be spent on.
Gym-balls, perhaps, or a few fantastic theatre trips, or a climbing frame, or something so inventively childlike no adult would ever guess it.
But the boy was right. They should have asked the consumers, the children, and they didn't. They probably thought that "proper" goals would look professional and make parents think that the school had wonderful facilities.
There is often a spendthrift sterility about the way adults make provision for children, and we should bow our heads and acknowledge that we are bossy and do not always know best.
It begins when we spend 20 quid on a specially designed "baby gym", and then go to visit some experienced bohemian multigravida and find our baby far more entranced with a soft plastic bottle filled with glitter and a few dried peas to rattle.
Babies need a fast-changing variety of interesting objects, not one or two overpriced designer rattles. Yet we surround them with things that look good to us, and we are ashamed to see them play with grubby old rag-dolls or bricks. I used to buy beautiful soft toys, witty toucans and penguins marketed by wildlife charities. But these were eclipsed for years by Mister Blue Lion, a hideous baby-blue dog thing won at a fair.
On it goes. We look at nurseries and primary schools, and once beyond the basic checks on cleanliness and safety we focus stupidly on the kit - its glossy varnish and tasteful colours and the elegant Corbusier-style portholes of the Wendy house. We find it harder to look dispassionately for evidence that children use this stuff.
We are upset by school buildings that look like bits fallen off 1960s air terminals, and impressed by pretty Victorian schoolhouses or dove-grey cloisters. But we should be listening to the voices and seeing how easy it is to run and create.
We see a playing-field with "real" goalposts and nets, and think, "Aha! Excellent facilities", whereas the real sign of excellence is children charging around in a friendly fashion, even if they are kicking goals between jumpers (jumpers are good because you can adjust the size of the goal to your own peculiar, nine-year-old, concept of the game).
Of course, we should spend money on children's environments - but the obvious, impressive things are not always what they need or want.
I went to a lovely primary school playground in Southampton recently. It was beautifully divided into quiet areas, rowdy areas and a walled ball-kicking area in a way which reflected not a desire to show off to parents, but with a real understanding of the variety of children's tastes.
I'll bet they were consulted at some stage.
Of course, we should not skimp on things which really make exercise and teamwork possible - but in their terms, not ours.
How many times has a local authority combined economy with an obsession about "facilities" and sold its school playing-fields to builders who promise to provide a leisure centre?
But ask the children, and as often as not they will mourn their lost den-building and ball-kicking ground. And, anyway, they can't afford many visits to the leisure centre to play a few sanitised games of squash or badminton.
And when they trail indoors to the school library, perhaps some are sorry that a whole bookcase full of shabby blood-and-thunder stories which they used to take home has been chucked out to make room for a bank of computers that keep breaking down.
Someone should have asked them. And listened to the answer.