While unchaste Vestals were executed by other means (live burial, cf. the comment on ampliatur a iudicibus in poenam?), the Tarpeian Rock from which Rome’s most loathed criminals were thrown was itself named after a Vestal virgin who had betrayed the Roman people: in the days of Romulus, the ill-fated Tarpeia had opened Rome’s gates to the attacking Sabines under promise of gold (Livy 1.11). The Sabines killed her shortly afterwords.