In California, if you've been convicted of a sex offense, have served your time, and are now out of jail, you still can't live near a school or a park or a daycare center.

This has the unintended consequence of concentrating sex offenders in areas that aren't near those (ubiquitous) institutions, and the solution of the neighborhoods seeing these concentrations is to build more parks.

I certainly understand the reasoning behind those laws, but it's an interesting problem. Since the laws are recognizing the likelihood of repeat offenses, maybe it would make sense to combine the restriction with some sort of treatment program?