Radiation is a fearful thing. Colorless, odorless, undetectable except by special instruments, it's one of those evils you can dismiss from your mind altogether, until the special instruments start registering. Then suddenly it's everywhere, or seems to be — a ubiquitous and ineradicable contaminant.

Children, as we all know, say and do the damnedest things. They mean no harm, they just know not what they do, sometimes. Their innocence is terrifying. Sometimes innocence looks anything but innocent. But all societies recognize it.

Children are not legally responsible for their actions. Parents and teachers may punish them in order to teach them responsibility. But it's a long process. Until it's complete, the evil they do, when they do evil, gets filed under "mischief," in recognition of the spirit in which it was — probably — committed.