The vanquished dies the Final Death. The only time one can expect the Conclave to be in agreement is in the need for secrecy. And even this tradition slips yearly. When Childre are Sired, it is usually with the permission of one's feudal master. This has less to do with fear of human discovery than one might expect.
Retribution is usually swift.
Revenge, should any survivors choose such a path, is equally viscious. The Clans of Ventrue and Tzimsce share political power in the cities with Tzimisce interest in the booming biotechnology and genetic engineering industries counterbalancing Ventrue holdings in traditional industry. The Tremere hold their own council. With ther Vassal Clans the Gargoyles and the Vryolakas, they remain apart from the other Kindred persuing their own mysterious goals. This has lead to a constant state of war between the Tremere and the Conclave.