It seems obvious to many people that if the consequences of an activity are sufficiently scary people will naturally avoid the activity. If the consequences of criminal activity are frequent death, injury or incarceration then that will be deterrent. Making children aware of those consequences and scaring them about the likely outcome of criminal behaviour will, surely, add the their motivation to avoid criminality.
So several community activists have put this into practice by designing programmes for local children that show them just how bad the consequences are with the explicit intention of "scaring them straight". One intervention is described like this:
Mr. Walker, 45, a coach with the Berkeley Cougars Youth Football and Cheerleading Association, part of a national league, put together a program “to scare kids straight” by showing them what happens to victims after the fatal gunshots or stab wounds.
Working with an Oakland funeral home, he takes youngsters to local graveyards and mortuaries, offering them an intimate look at how bullet-ridden corpses are taken from crime scenes to cold storage, then patched together for viewing before cremation or burial.
The original "scared straight" idea seems to have come from a programme run by inmates of Rahway State Prison in New Jersey. This programme has been the subject of two TV documentaries. The producer is quoted (here, but paywalled):
I can't tell you how many people have come up to me and said: 'I was a juvenile delinquent and when I saw this, I stopped, and changed.'
So this seems like an obvious idea that works: deliberately scare people by showing them the possible consequences of their actions and deter them from crime.
But the simple question is: do these schemes work? That is, can we show that the people exposed to them are less likely to commit crimes than those who are not exposed to the schemes?
PS I do have a view on the evidence, but I want to hold back for now to see whether broader evidence emerges from other's research.