I am brain dead right now (anyone who reads my journal knows why) but I am certain that some of the examples given where factual and not just "for examples". Specifically, the case of children killing their parents before they were too old. I can't recall the exact culture at the moment, but I believe it was practiced among the tribes who inhabited the far northern islands of Japan and possibly among the Inuits too. The idea was that resources were very scarce and when a person became too infirm to contribute to the survival of the village it was a noble thing to die. The child, usually a son, would carry the parent up into the mountains (usually by this time the parent was too infirm to make the trip walking) and leave the parent to die of exposure in the cold. It was considered a noble death, and accepted as necessary by all parties in question.