How to get rid of a sex offender

Most locales that have enacted laws prohibiting registered sex offenders from living within certain zones have, as part of the law, prohibited same from moving back in once they have left.

What this means is that if you live in such a zone with a registered sex offender, and he is forced to "move out" due to his house burning down (according to news reports sex-offenders' houses are unusually subject to this and though "accelerants" like gasoline are usually found nobody has EVER been charged for committing such a crime) and he has to take up a new residence... he CANNOT move back. Ever.