There are plenty of middle- and upper-class families who find the amount paid in Child Benefit completely superfluous. Someone who can afford to send two or three children to a private school does not need several hundred pounds a year extra.
The savings created could be used to put in place more rigorous assessment to establish whether lower-income families really need the Child Benefit and what it is being spent on. How many parents currently claiming they couldn't afford to bring their children up without the Child Benefit smoke, or have a subscription TV service? Why can't home assessments be carried out to ensure the money is being spent on those children? Perhaps for families with a lower income, there could be something similar to the Child Trust Fund whereby the Child Benefit is reserved for each child for when they are older. This would prevent the parents spending the money on other things.
I would also like to see tax advantages put in place for childless singles and couples. If we are encouraging childbirth in a society which is already too overcrowded, we are sending the wrong message.
Why does this idea matter?
Simply it would create savings and make society fairer for children who are genuinely disadvantaged. It might also lead to fewer births which is good is a society which is too large, and better for the environment too.