I think the idea is that the Bloodlines have divorced themselves from the Antediluvian's blood. Although this would not protect them from social manipulation of their elders it does protect the line from powers that depend on lineage. Dominate has at least one. I imagine so does other Disciplines. I imagine this is why Caste and Bloodline are such important distinctions. A caste remains of the blood while a bloodline may or may not....