They can't do it with the same Ethereum address. NFTs are minted by a transaction associated with a unique address. Each ETH address develops a reputation over

They can't do it with the same Ethereum address. NFTs are minted by a transaction associated with a unique address. Each ETH address develops a reputation over time. Couple this with a listing on a public marketplace and public confirmation of your ETH address (could be artist's Twitter profile, a decentralized ID, a personal website confirmation, a NYTimes ad, etc, whatever works). Not all NFTs need the same level of provenance guarantees. These are very broad abstractions.