The law was challenged by four parolees who were released on a new grant of parole after the effective date of the proposition for non-registerable offenses but who due to previous convictions have a lifetime registration requirement. Compliance with the Proposition 83 requirements was made a condition of the new parole grant.

The parolees argued that the law was illegally being enforced retroactively. The majority opinion finds that it is not a violation of either Penal Code Section 3 which prohibits the retroactive enforcement of criminal law unless the law specifically allows retroactive enforcement or the ex post facto sections of the state and Federal constitutions. The court found, as to the four petitioners, it was only being alleged as a condition of parole granted after the effective date of the proposition and it was only governing activity that happens after the effective date. Generally ex post facto laws are prohibited because they punish activity without prior notice of the illegality of the activity. Here the petitioners were given notice when they were placed on parole that they could not live in certain areas. They were not being punished for the original offense which led to the registration requirement. Rather they could be punished for moving into certain areas when they were paroled after the proposition’s effective date.

As to the constitutionality of the stay away requirement, the Supreme Court requested superior courts in the county of parole to hold hearings to determine whether the residential restrictions violate the petitioners constitutional rights. The court indicated that there might be a constitutional violation if there was only a limited area in the county of parole where the petitioner could live. Many sex registrants have become homeless or at least have registered as being homeless because the parole boards have treated the homeless as not being in violation of the residential restrictions as long as they do not stay in an area within 2000 feet of a park or school for an extended period of time.