According to gazetteers of the Hualien-Taitung region, this precipice as known by this name because "those walking across it are in a constant struggle, and even the relationship between father and son is difficult to maintain, so that they no longer acknowledge one another ...." This should give you some idea of the peril of this bluff.
根據花蓮縣志記載，之所以取名親不知子，是因為「行人戰戰兢兢，雖父子之親亦難扶持共濟，一若不相知者… …」以形容此崖之險。