Perhaps it would have been an error in my attempt at utilitarianism, if indeed it were an attempt at utilitarianism; to me however it does matter whether someone is guilty or innocent when executed, and I think it also matters to most people (attempting Rawlsianism?) objecting to my comment on the grounds of any execution of an innocent person being unacceptable. (Can I say that the error in their attempt at Rawlsianism is that they don't also oppose cars which regularly cause deaths of innocent people? I guess I can say it except for the part where I attribute opposition to cars to a philosophy that I never studied in depth.)