The increasing use of diversion programs as alternatives to the institutionalization of both adult and juvenile offenders is having the side effect of widening the net of social control by criminal justice personnel to the families of diversion's targeted clients through family-oriented treatment programs. When the families of the targeted clients, especially their siblings, are unable or unwilling to cooperate, the attention of criminal justice personnel is called to behaviors that would otherwise have escaped notice. On the other hand, adult offenders referred to diversion programs who are unable to meet the program requirements are subject to informal double jeopardy; they are returned for prosecution on their original charges, prosecuted vigorously, convicted, and placed on probation supervision. Diversionary powers encourage members of the criminal justice establishment to place individuals into the system, especially juveniles, who would otherwise be left out as borderline cases. Juvenile clients' perception of the differences between diversion and incarceration as reported in a 1979 study by Paternoster is mixed. The majority of diversion's targeted clients feel that diversion involves stigma and social liabilities similar to those of incarceration. Since diversion programs are administratively controlled by the official justice system, staffed by justice personnel, and physically based in official justice premises, they are a supplementary rather than alternative function to the justice system. Evaluators of diversion programs must differentiate between proper (system insertable) diversion clients and net-widening clients (noninsertable subjects). They must also be aware that diversion programs are increasingly widening their net to include whole families of diversion's targeted clients. Therefore, they develop capacities in this area, using self-report measures to explore family reactions to treatment experiences. Evaluators can play an increasing role in shaping correctional policy decisionmaking by contributing to the scrutiny and accountability of diversion programs to help eliminate ineffective and socially dangerous ones. Explanatory endnotes and 120 references are appended.