Even without outright murder, cultures have still found a way to eliminate "undesirables"

According to Douglas Oliver and Lev Shternberg, [suicide] was also the response to incest among the Solomon Island Siuai and the Gilyak. Oliver notes that when a Siuai couple who "flaunted the convention against [sibling] incest by openly living together" were censured by their relatives the girl committed suicide by hanging, and Shternberg found that among the Gilyak "it was not uncommon for lovers belonging to prohibited categories to kill themselves at the instigation of their relatives. In one of the songs of such an unfortunate pair the woman complains that her sister called her a bitch, and her beloved a devil because he was her uncle; and that all her loved ones - father, mother, and sister - kept telling her, 'Kill yourself, Kill yourself.'"

- Arthur P. Wolf, Incest Avoidance and the Incest Taboos