due to mature subject matter, viewer discretion is advised. listen up. there is to be no talking, period. one behind the other, single-file line. ry oh did >> a prominent research study estimates that 1 in 31 american adults are either incarcerated, on probation or on parole. just as interesting is the fact that many of the inmates we've met have told us they actually prefer serving out their sentences in prison to being freed on parole. >> they say it's difficult to find work and that the parole rules are so strict that they can make a simple mistake and end up in prison where they cause more pain for their families and further tarnish their reputation. >> few inmates illustrated the problem of walking the thin line of parole better than one we met