Whether Hannah's disappearance was an accident, foul play, or something else is still unknown. But a public plea like this can help to generate new leads, says international kidnapping negotiator Julio Gomez, CEO of Trident Crisis Management Group.
He estimates that in 10% of cases, public pleas yield tips that can be used to aid in locating the missing person.
In cases of kidnapping for financial or political purposes, pleas by family or friends can spur captors to enter negotiations that can accelerate the hostage's release.