Why is it that forbidding sex offenders to live within 2,000 feet of a school, childcare center, ...

Why is it that forbidding sex offenders to live within 2,000 feet of a school, childcare center, library, pool, or park may actually lead to a higher risk of re-offense?
 
  a. This restriction makes many sex offenders feel like those in the community will never give them a second chance, leading to increased anger, aggression and acts of violence.
  b. Many sex offenders go underground because of their limited housing options, leading to greater freedom and increased chance for re-offense.
  c. By giving sex offenders a list of places where they must not live, they are essentially being handed a list of the most optimal places to find their next victims.
  d. The many restrictions placed on sex-offenders causes higher rates of depression, which often creates an increased desire for them to commit sexual offenses.