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If your race has access to FTL communication, and has some unique methods for gaining access to secrets (super quantum computing code cracking, seriously capable spies, hackers supreme, or even telepathic, precognitive, and/or psychometric snooping), then simply threatening to spill secrets across the galaxy in real time could prove a very effective deterrent. 

Depending on the method in question, this could be tailored to individuals, specific ships, or groups and organizations, up through entire political structures, social groups, and cultures.
Might not prevent them from getting killed more and again, but others of their race can sure make them regret it every time.