Allowing the population to know where sex offenders are would encourage vigilantism.  Vigilantism is a real threat to those publicised as sexual offenders, especially those whose sexual offences involve children. For example, in the UK a vigilante published a database naming almost 10,000 paedophiles1, and some misdirected vigilante attacks have been committed against those with no criminal convictions, such as a paediatrician2.  Therefore, there is the possibility of harm occurring in that offenders who have served the punishment the justice system feels is adequate being subjected to further punishment and violence. Furthermore, there is the possibility of mistakes being made and people being subject to violence for no reason.  1 The Telegraph, "Internet vigilante publishes database naming 10,000 paedophiles", November 2010, 2 The Independent, "Vigilante mob attacks home of paediatrician", August 2000,