They're the ones who get too greedy at Christmas, who always want more than their parents could ever afford and look disappointed when they open their presents on Christmas morning.
Nobody tells them.
Sure, Santa comes down the chimney, but the presents are actually ordered online by Mum and Dad from Santa Claus Inc.. And Santa needs greedy children as raw material for those lovely toys.
Ever wondered why you never see Santa with an empty sack, even when all the presents are delivered? Careful what you wish for, children.
Some children never grow up.