I saw a documentary about a prison isle. Not sure if it was the same 'prison', but it was somewhere in Scandinavia.
I understand that these 'punishments' are debatable, but we should realize that many of these prisoners will leave the prison (or this isle) one day (murderers don't deserve this IMO, but that's another debate).
Criminologists explained that most of these former detainees behaved much better after their detention than 'normal' prisoners.