According to @VitalikButerin (X/Twitter, Oct 26, 2025), a core blockchain property is that even a 51% attack cannot make an invalid block valid, so 51% of validators colluding or suffering a software bug cannot directly steal assets on-chain. According to @VitalikButerin (X/Twitter, Oct 26, 2025), this guarantee does not hold if users or protocols trust the validator set to perform tasks the chain does not control, where 51% of validators can collude to output a wrong answer with no recourse. According to @VitalikButerin (X/Twitter, Oct 26, 2025), this highlights trading-relevant risk for systems that depend on validator-majority outcomes for off-chain decisions or oracle-like answers, as the trust model shifts from objective consensus security to social trust in validators.