I suppose my original post was incorrect. The thief's life is never worth less than my laptop. But the thief's life, to me, is worth less than my own life. Society would most likely agree with my assessment of value. A productive, peaceful citizen is better than a harmful citizen, which is why we have self defense laws, for those specific situations where I am forced to choose between my life and his life (although I don't know how I would make such a choice, I'm certainly not qualified to defend against a criminal who is armed with a knife...)

I don't believe that I should ever have to be responsible for another person's tendency towards violence. It may be unwise to fail to account for such tendencies, but to be legally responsible for them is wrong. Had this situation turned violent, the woman and her neighbor would be no more responsible for that unfortunate outcome than a rape victim is to be blamed for wearing revealing clothes (again, perhaps an unwise decision, but certainly a legal and moral one).