At the same time, it is incredibly easy to fake being sorry. In addition to that, in the case of an innocent being held in jail they would have no real reason to be sorry for what they didn't do. (I could accept that this latter point doesn't hold, if the prisons simply assume that wrongful convictions don't occur and aren't their problem if they do.) (I recall this scenario from a study we did in school on wrongful convictions. One particular individual -- who served 30 years and later had his conviction overturned after he was released, explicitly refused to apologize; that would mean he was guilty.)