It may well have been that his crime was acting like he knew how to do it while being 8. I had old people like that around when I was a kid. And I was a very respectful kid
I reckon he knows if you’ve been bad or good because of the parents’ assessment of their children’s goodness. That is not a specific Santa power, except in as much as the power of Santa to get that parental assessment is a power
I think it has to be based on the parents, as clearly bad kids still get presents, and only their mother thinks they’re good.