Abductors don't need to be everywhere. They just have to be a plausible threat to affect the thought process of a parent that's deciding whether or not they are going to leave their child completely unsupervised and unattended.

Maybe if the media didn't have a fetish for covering the incidents that do happen. Maybe if there wasn't a vocal subculture that crucifies parents for leaving their children to their own devices. Maybe if the thought of having the center of your world being beaten, violated and murdered at the hands of a stranger wasn't so mind-numbingly horrific. Maybe then this trend would start going the other way.

Or not? Sure parents used to let their kids roam free. They also let them ride in the back of pickup trucks and beat their asses when they did something wrong. There's probably a healthy middle ground.