“Imagine if you will that the following scenario takes place in a free society: Someone has information about a group who was committing horrible acts of violence across the globe. The leaders of the group claim their rights were violated by the individual, and they convince a court to find this person guilty. The group convinces the court that the individual’s actions are so heinous that he must spend the next 136 years of his life in jail. Now, on the other hand, many of the people who were informed of the horrible misdeeds of the group are not convinced. Some of the people are so adamant in their support, that they offer to serve a portion of his sentence in order for him to go free.”
http://dailyanarchist.com/2013/08/10/substitutionary-justice-in-a-free-society/