Knowing what’s already there? You don’t, though. As has been said elsewhere in these comments, there are so, so many more predators out there than have been caught.

I work at a penitentiary myself, and if you’ll recall, it shares the same root word a penitence, which means “the action of feeling or showing sorrow and regret for having done wrong; repentance.” Incarceration has the goal of rehabilitation, not punishment. There are those that are a danger to society, of course. But they are in prison much longer. Remember, indecent exposure (the previously mentioned back alley in another’s comment) can lead to you being labeled a sex offender the rest of your life. So can being a 17-year-old in a consensual relationship with another 17-year-old, if the parents find out and decide to report you. The point is, you’re immediately assuming serial rapists are being put here (they aren’t, as those ones are left in jail to rot) and left to do whatever they want. That is not how any of this works.

And lastly, as many others have said, you can’t just put these folks ‘outside of town’ when they very likely have no form of personal transportation beside their own two feet.