The way the media cover an event influences whether there will be repetitions. For example, if a fan runs onto the field during a baseball game, the broadcast cameras usually avoid showing pictures of the fan. The TV producers know that the fan on the field is seeking attention, and that, presumably, getting his picture on television will reward him. Moreover, broadcasting the man’s antics would encourage copycats.
Killing time at a baseball game is a tiny misdeed, compared to killing people, but many media decisions have the effect of encouraging copycat murders.
— Reducing the risk of copycat killers, David Kopel, 2007