The question most asked of children these days before the arrival of the Magi is "Have you been good?". A formula frequently used by adults as a condition, and even blackmail, to receive some or no gifts on Kings night.
They are often led to believe that His Majesties, generous and selfless characters in theory, constantly observe them, 24 hours a day, 365 days a year, taking good account of their behavior. Of course, these days the control is more exhaustive. Depending on how they have behaved and if they have done what the parents want, they will bring more or less gifts, or coal.
Of course, I do not believe or like to make children believe that the magic of Christmas gifts depends on whether one day they have not done their homework or have done something wrong. Children are children, and naturally, there are days that do not behave as well as parents would like, but they are not bad. I'm with those who proclaim the Stop at "Have you been good?".
The tradition of coal is curious, but I don't like it when it's used as a touch of attention. Like saying "Hey, you've been so good to us". I think of a child's disappointment face when I see a bag of sweet coal instead of a gift.
On such special dates for the little ones, you should forget the "Have you been good?" to leave prominence to fantasy, illusion and generosity that is the true essence of Christmas. Don't you believe it
