Moral luck is a tricky concept. The examples you offer in your question illustrate why. Philosophers use the notion of moral luck to refer to situations where a person is subject to moral judgment for something which is (at least in part) outside of her control. A common example: Two drivers side by side speed recklessly through an intersection. A pedestrian enters the intersection from the right, and the driver on the right strikes her. The driver on the left speeds through the intersection without injuring anyone. That the driver on the right struck the pedestrian is to some extent a matter of luck (the pedestrian could just have easily having been entering from the left side). So too, that the driver on the left did not strike the pedestrian is to some extent a matter of luck (again, the pedestrian could just as easily entered from the left with the result that she is struck by the driver on the left). In his seminal article on this topic, Thomas Nagel distinguishes four different kinds of luck. (http...

Before reporting the supposed crime, I'd ask myself a lot of questions: First, how strong a piece of evidence is an admission of guilt? Increasingly, psychologists and legal scholars are discovering how remarkably common "false confessions" are: http://courses2.cit.cornell.edu/sociallaw/student_projects/FalseConfessions.html Is there any reason your relative might admit to this crime aside from having actually committed it? Second, you say that there is not enough information to lead to an indictment or trial. But of course that determination isn't yours to make, and it may be that once your relative is under suspicion, an investigation will yield more information about the crime, information that could lead to your relative's being indicted. So do you really know what you claim to know, i.e., that there's not enough evidence to indict (as opposed to your not having access to sufficient evidence to indict)? Third, you say that there aren't any "significant real world consequences" for the relative if...

I’d be interested to know exactly what’s motivating your question, but here’s a stab at the reasoning that might be behind it: Suppose that a society is (collectively) obligated to care for the disabled. Caring for the disabled imposes burdens on the rest of society. But it’s wrong for us to knowingly act so as make ourselves (more) burdensome to others. So it would be wrong for us to knowingly act so as to disable ourselves, and since it is permissible to permit others from wronging us, it is permissible to prevent people from disabling themselves. Before we address the soundness of this reasoning, I’d note that very few disabled persons have chosen to be disabled. In the vast majority of cases, disability either doesn’t stem from a person’s choice at all (the disability is traced to genetic or environmental causes) or results from a choice that carried a risk of disability (working in a dangerous profession like logging, engaging in a dangerous form of leisure). Most societies address these with...