[mckmk]

>Barring all that, they could just not recognize the owner and send police to physically remove someone who thinks they own it because the have the NFT. That's one reason why some people like bitcoin so much, the government can't (easily) take it from you by force (because there's no physical aspect to it) like they can a home or gold.

If this were to happen and the blockchain and the physical world diverge, how would potential house NFT buyers know whether the physical house purportedly linked hasn't been overridden by local government? If the answer is for local registries to publish a list; then that list is the only thing that matters. The entire blockchain component becomes completely superfluous and a centrally managed electronic exchange would be faster, easier and cheaper.

[cableshaft]

You could check if the NFT was still valid by calling the smart contract directly if they provide public functions for it. No need for a published list by a centralized authority (beyond whatever you're using to call functions on a smart contract, like I'd probably use Etherscan if it's an ETH contract).

And calling read-only functions (doesn't write anything to the blockchain) doesn't cost anything.

I didn't think of this with my original post, but there are NFTs that are used for access to things that people already say "don't buy these on the secondary market, legacy, no longer used". Not too dissimilar of an idea. Those NFTs are still in those people's wallets but it no longer provides the benefits associated with it.

Like the old Premint pass, which gives you access to tools to help launch NFT projects. The description for the old pass says "DO NOT BUY THIS PASS. This pass has been replaced with the PREMINT Creator Key" and the banner image says "THIS PASS IS NO LONGER VALID": https://opensea.io/collection/premint

[mckmk]

This does not sound like good system design.

“NFTs create a frictionless easily exchangeable market for goods… BUT make sure you check with the people, project, company or government that has authority over this good as to whether this particular NFT is actually a useful representation of anything. Because, at any arbitrary point they can just decide to not honor any of these.”

Why not buy the good directly from this party? Then at least the government has authority and can enforce your right to the product or service or at least a refund?