But it's in many cases not 'your' kid. You have invited someone else's kid (with unknown upbringing) to let it play with yours (or alone at your place, but that's an awkward example). You can instruct it to play around, but who's at fault when this invitee starts to make a mess all by itself.

Anyway, in the case of hacking, as we can read in the news, it is the kid doing it's 'explorations' unsupervised from its parents house.