I think if you re-examine what we know traditionally about the predictors of criminal reoffending, these individuals don't present a large volume of those things, such as unstable employment, family dysfunction, and mental health challenges. They will fall outside the ambit of, perhaps, detection. We don't know. Maybe they do desist.
That's why we require that kind of long-term, focused study to disentangle those two areas they are hypothesizing. We could hypothesize that they are rehabilitated. It would appear that they are. But how do you confirm that? How do you actually prove that, other than by the fact that they don't become involved again with the criminal justice system? That's the only measure we usually use: an officially recorded new conviction for crime.