To be honest most of the guys I went to boot with didn't improve as people much from the experience. But it might be a good approach, it is worth remembering though that boot camp and the service don't revolve on telling people what scumbags they are, it revolves around telling them that and also telling them they're a cut above the normal man frequently too. That the outcome of this training if they embrace it will be to join them to an elite group of badasses worthy of respect and praise who do badass, respectable, praiseworthy things. We don't tell prisoners that, it isn't true. If they pass their training they have a decent chance of being allowed to enter society again as moderate pariahs, except in certain groups where their prisoner status is seen as a minor detail or a plus, needless to say those groups are the people we don't want them hanging out with. It isn't like we can, or really should if we could, get average citizens to welcome ex-cons into their workplaces and communities with open arms.

As to open-ended sentences, I don't know if I could approve of that for anything short of the most serious crimes, we already have the ability to extend sentences for additional crimes in prison, and while Cool Hand Luke stuff isn't too common I really am not too comfortable with a scenario which allows a car thief who commits no other crimes in prison to die of old age there because he didn't pass their tests. Same reason I'm uncomfortable with a lot of the recent resurgence in talk of rolling back all the measures we put into place to make it harder to dump someone in an asylum and throwaway the key. If we conclude someone is unreformable then I tend to think we should just kill them quick and clean, but I have doubts about the reliability of tests and observation of reform when our 'experts' at the field don't seem to have made much progress at really treating mental disorders or 'curing' criminals. I'm not saying accurate diagnosis and evaluation is only possible if you can also provide a reliable cure, but it sure raises my confidence when that's the case.

People often want to turn this into a science, so to speak, which I'm all for, but that also entails usefully accurate predictions of results by method and we don't seem to be there yet. It's an educated guessing game at best, doing parole and similar, and until those results are getting me into the 'beyond reasonable doubt' ranges of accuracy I'm not willing to contemplate open-ended sentences except for stuff I'd already be considering life imprisonment or execution for.