Genuine question: What's to stop someone for minting another block, with something that has previously been minted-e.g. Dorsey's first tweet, and pawning that o

Genuine question: What's to stop someone for minting another block, with something that has previously been minted-e.g. Dorsey's first tweet, and pawning that off as the real deal? (nb4 the tweet/NFT is too well known. Consider lesser NFTs.) I'm sure a lot of people will catch on, but that certainly won't be everybody.