Under the quarantine model of criminal justice, potentially dangerous individuals have their freedoms humanely restricted to prevent societal harm. Prisons are believed to be unnecessary, and restrictions aim to minimise the infringement of civil liberties.
This can range from minimal interventions, such as preventing individuals involved in bar fights from buying alcohol, to house arrest for the most dangerous offenders. If judged to be necessary to prevent societal harm, restrictions can also be applied to individuals who have not yet committed crimes (e.g., preventing a bullied teenager from buying a gun).