At the heart of the movement toward mass incarceration on the one hand, and the gating of communities on the other, is an identification of security with spatial separation from those perceived as dangerous.
The latest form this mandate toward risk segregation in space takes in Jessica's Law, the ballot initiative approved overwhelmingly by California voters in 2004 that requires convicted sex offenders to reside more than 2,000 feet from schools or parks. As reported in the Sacramento Bee, more than 2,000 sex offenders paroled from prison since the law went into effect, are in violation of the law.
California Department of Corrections and Rehabilitation Secretary James Tilton, acknowledged that the state does not have the capacity to achieve complete compliance or to subject every such offender to GPS monitoring, also as required by the law.
Beyond the question of enforceability, is the question of why modern Americans associate security so closely with walls and other forms of physical separation. The sex offender who does not live near my child's favorite park, is not necessarily less of a threat to that child.