Firstly, given the low % of offenders who commit serious crimes within 6 years is around 10%1, this seems like it may be a marginal issue.  Furthermore, it seems unlikely that people who already know someone will stop associating with them merely because of their stigmatization. Family, for example, tend to be very forgiving, as are close friends, who are likely to believe their long-term view of somebody is more accurate and to forgive a mistake. Such people will be able to ensure a person is not alienated from all society.  This may also be a benefit; if an offender has a tendency to commit sexual offences within relationships, it may be useful to limit his relationships (or at least warn their partner of such a tendency), such that this is not likely to occur again.  Finally, it can be shown that if this policy does increase the deterrent effect to first-time offenders, this may be more important. This is because some people will be prevented from ever being imprisoned, associating with other prisoners, and acquiring a criminal record