What counts as leverage depends on the time and place. Not too long ago you might have blackmailed someone for smoking weed back in the day. Or for being born out of wedlock. Or for being gay (well, that one is still potent in a lot of places). Kids being stupid is normal, and something tells me that if this happened in, e.g., Amsterdam, the kid would have gone straight to his parents and the blackmailer would have gone to jail.