Arbitrum, an Ethereum layer-2 solution, has not seen a single fraud proof submission since launching its mainnet in August 2021, according to Ed Felten, co-founder of Offchain Labs. The platform's interactive, multi-round fraud proofs allow a layer-1 verifier contract to decide if a fraud-proof submission is valid, slashing the fraudulent validator's stake if necessary. Felten attributes the lack of fraud proof attempts to the strong disincentive of losing one's entire stake. Arbitrum is also rolling out a new iteration of fraud proofs called the BOLD protocol, which aims to provide faster guarantees for challenges.