"It is not unusual to incarcerate offenders for terms longer than those which may otherwise be imposed, as a ‘preventive’ measure designed to protect the community. Such forms of imprisonment are generally referred to as ‘preventive detention’ schemes. However, the DPSOA [Queensland's Dangerous Prisoners Sexual Offenders Act] is unique because it authorises the reincarceration of a sex offender who has served his or her term of imprisonment ..." (Quoted from article)