At this moment nothing. The more centralised markets - SuperRare, Nifty Gateway - probably do some form of KYC. That's the risk you take when using fully permi

At this moment nothing. The more centralised markets - SuperRare, Nifty Gateway - probably do some form of KYC. That's the risk you take when using fully permissionless markets, but I'd say if you are a collector, you take 5 minutes to check whether the artist exists. I don't buy anything unless the artist is on Twitter/instagram linked to his profile. There are ways to verify identities on both Tezos and Ethereum blockchains which is usually how I look into and make sure the artist is legit. I myself own an Ethereum Name Service and Tezos domain (.eth and .tez). For a few dollars the owner of one of the main tezos scan websites also creates verified identities using Twitter profiles. Takes a bit of effort but it is worth it. Having an active twitter account is also a big thing in the NFT space, it helps enforce a minimum level of difficulty to art stealing.