All of the censors vote on if they have been tampered with. They will leave a record of their votes on the blockchain as Bob tampers with them in real time.
I’ve heard many scenarios like “transfer of human organs” as a scenario for blockchain, but I’m skeptical that blockchain solves problems in the tangible world all that easily. It is my perception that blockchain is great for trustless information assets, but not great for trustless tangible assets.
Blockchain can’t stop a human from stealing an organ and replacing it with a different organ. Even tracking shipping containers, which was high profile a few years ago, only requires a human to make a mistake in loading a boat to throw off the database.
In tangible-world-to-information-storage scenarios, the hard part is not the information, but the guarantee that information matches the real world. In my view, the claim that blockchain solves for a trustless tangible world is naive.
It's hard to imagine a solution to these problems because we are so far away from highly functional examples of this tech in action in the "real" world.
That said, engineers live to solve problems in better, smarter ways.
I personally believe it is naive to bet against innovation in this sphere, but we both shall see if we are so fortunate.