While I disagree with you, I appreciate your trying to bring some thoughtful discussion to the abortion topic. We both make some fine distinctions around this issue, and I followed the thread and read your "famous violinist" analogy. I'll try to answer your questions to me by working at least to some extent with your own analogy.
I agree with you that no person should be forced to give life support to another person just because "fate," "chance," or "bad luck" threw them together. Likewise, no person should be forced to give life support to another person because the other person used force or fraud to get into a position to receive life support. If the "famous violinist" has hooked himself to my kidneys without permission, I'd not wait nine months to be rid of him even if it meant his death. This situation is why I wouldn't punish a rape victim or her doctor for aborting the child conceived during rape.
On the other hand, I disagree with your notion that a woman shouldn't be responsible for the child conceived during consensual sex. Your article suggests that pregnancy is analogous to someone leaving a window open to enjoy a breeze and having a burglar enter through the open window. I think this analogy is badly flawed when applied to abortion. The burglar is entering the home with criminal intent. The burglar is guilty of doing harm the moment that he enters the home, and the resident has reason to believe that he or she is in imminent danger. Using lethal force against the burglar is a reasonable act of self-defense. Conversely, the unborn child does not come into existence by his or her own choice. The unborn child does not come into existence as a result of his/her own criminal or malicious intent. Furthermore, in spite of the ranting of some proponents of legalized abortion, a normal pregnancy is not a significantly greater health risk than abortion. Using lethal force against the unborn child is not a reasonable act of self-defense. Finally, the writer of that web page suggests that an innocent person may innocently wander into one's home. I can't imagine an innocent person innocently entering through a window left open for the breeze, but let's assume that a door was open and someone entered because he thought it was another person's home. Unless this innocent intruder did something else that represented a reasonable threat, a resident who killed the innocent intruder without cause would be criminally liable.
I'll take your home visitor analogy a step further. A person is at work when a burglar enters his home, falls, and is injured in a way that he can't be moved without risk to life. As far as I'm concerned, the resident of that home has the right to insist that the burglar be taken out of the home even if movement kills the burglar. The resident didn't ask to have the burglar in his home, and anything that happens to the burglar is the burglar's problem. On the other hand, if the resident invited a friend to visit, and the friend falls and suffers the same injury, the resident does not have the right to insist that the friend by removed at risk of life or permanent injury. When one invites someone to visit, this risk, however small, is one that the resident must bear. If the event happens, then the resident must accept the consequences. The analogy to pregnancy should be obvious. By consenting to sex, a woman is accepting a risk that no matter how many precautions she takes, an innocent person may become dependent on her for life support. If that event occurs, she's obligated to provide that support.
To answer your specific question about RU486, I disagree with this drug because it kills an unborn child that the woman knows is there. I agree that there can be some ambiguity about whether a fertilized egg that hasn't implanted is really a person. However, by the time a woman knows that she's pregnant, I believe that the unborn child inside her is already a person. I don't have a big problem with a true "day after" pill, but RU486 is just a chemical abortion directed at a child that the mother knows is there.
Bill