According to TechFlow, Ethereum co-founder Vitalik Buterin responded on the X platform that "all major L2 networks in the mainnet can technically steal user funds." He said an important detail: the rules of Phase 1 require that the code can only be overturned when the security committee reaches a 75% voting threshold, and the members who block the quorum (i.e. ≥ 26%) need to be from outside the company. Both Optimism and Arbitrum meet this requirement. Therefore, these organizations cannot unilaterally steal funds.
