This is about confronting the possible downside of the position you take. It is about realizing what the position you advocate means and accepting it. I can accept a DP proponent that acknowledges that a possible outcome is that an innocent is executed but accepts that as the part of a greater good. His/hers position is well thought out and i only applaud that, reasonable people can disagree about though moral issues nothing wrong with that.
I allready admitted that my position has an equally though dilemma. I dont kid myself i know that this will happen, but i accept it because i think the other option is worse. Not everything the other side says is a lie.