The catch and release system we have either creates a career criminal or a changed person. If there volunteering at a church I would call them reformed.
In the risk management seminars on this subject that I attend, a consistent theme is that sex offenders, especially those who offend with children, gravitate toward places where children are. This is why you see a disproportionate number of these offenses occurring in school settings, Scouting, religious settings, healthcare settings, retail geared towards children and the like. Volunteering can be especially problematic since many people think the best of the volunteers, or they are in a volunteer setting that does not screen them, either at all, or adequately.