The whole Li'l Slugger/Shonen Bat phenomenon was derived from actual incidents in Japan of schoolkids committing murders with baseball bats and so forth. And in Japan, in the interest of protecting a perpetrator's privacy, he'll only be referred to publically by way of a pseudonym such as "Shonen A."

Paranoia Agent has no basis in fact when it comes to specific circumstances, of course, but many of its integral plot points do bear some pretty significant influences from modern Japanese society.