Zoned out: sex offender residency restrictions.

A JERSEY City ordinance that took effect in December bars sex offenders from living within 2,500 feet of a school, day care center, park, playground, sports facility, library, theater, or convenience store. Together those zones cover virtually the entire city.

Across the country, politicians are eager to draw circles of protection they claim will keep children safe from molesters. Hundreds of municipalities and more than 20 states have laws that restrict where sex offenders may live. But critics say these zones of exclusion are ineffective, sometimes counterproductive, and frequently unjust.

Consider the Georgia woman who was labeled a sex offender because she performed fellatio on a 15-year-old when she was 17. In 2005 she had to move because she was too close to a day care center. Now she and her husband may have to move again because they're too close to a school bus stop, a location added to the state's list of restrictions last April.

Georgia's law, which has been challenged in federal court, also would exile all 490 registered sex offenders in DeKalb County. Some are genuine predators, but most are men who as teenagers had consensual sex with younger girls. The law even applies to sex offenders dying in nursing homes.

Other states have narrower laws, but police and prosecutors still worry that onerous residency restrictions will push sex offenders onto the streets or discourage them from complying with registration requirements, making them harder to track. Critics of the laws also note that around 90 percent of molesters victimize relatives or other children they already know, the sort of situation where zones are irrelevant.

Even when sexual predators are strangers, there's nothing to stop them from roaming beyond their immediate neighborhood. "We don't see any evidence of a connection between where a person lives and where they might offend," the executive director of the Iowa County Attorneys Association told The New York Times in November. An official at the National Center for Missing and Exploited Children added that "these laws may give a false sense of security."