Personally it doesn't matter to me as long as only new sentences would get affected by it. You see... if you commit a crime and ended up in jail.. you choose that way. Here it would be you make the decision to risk such treatment(which would have to follow certian standards anyways) when you commited the crime. So therefore I do not see a lack of choice.
However, it does still leave a somewhat bad taste in the mouth.. but as long as standards were fair and followed and we knew that they commited the crime then I could see it as an extreme sentence that could be handed down.
Also my own opinion on that would be; if they got the sentence due to a lose of control due to anger or too much alcohol, then if they were used for the advancement of science.. then the tests that they were used in must have the goal to aid those with the same problem. Thus, this could be used to maybe help cure some of the sicker people in our world.
