Winnie Hu and J. David Goodman, reporting for The New York Times on a case of child abduction on July 17, 2013:

You have a lot of people on the road at that hour,” said Robert Hoever, director of special programs at the National Center for Missing and Exploited Children, which tracks Amber Alerts across the country. “You’re looking for those eyes and ears to try to find that child.”

By Wednesday afternoon, the police said that they had found Ms. Lopez and her son in “good condition.” Ms. Lopez was arrested and charged with custodial interference. The police said she was found after the Amber Alert led to a tip to the department’s Crime Stoppers hot line.

And the key risk for non-mandatory AMBER alerts, later in the article:

One former state law enforcement official, Michael Balboni, said the alert system should be used prudently.

“It is crucial that emergency notification systems take every precaution to never ‘cry wolf’ or alert needlessly,” said Mr. Balboni, former deputy secretary of public safety for the state. “The risk is evident: If the public loses faith in the system, they may stop participating and the purpose of the system will be lost.