-could an address be added to a central repository (yes, centralization) that could track illegal activity? You might be able to answer this since - can we track the IP of where the coins are received assuming they're downloaded into a wallet? I know the coins don't literally exist in the wallet, the wallet is just a bunch of keys that unlock the transactions in the blockchain (or at least as I understand it). But since the blockchain shows a lot of information such a coin origination and propagation, does it also show if a wallet was being used to receive the coins?
However tracking even the source of a transaction is not guaranteed, since someone can simply send it to another bitocind of their own choice and not send it to anyone else (but instead that target bitcoind propagates it for them)
-I know one of the key features of BTC is it's lack of centralization. No overt governing authority making rules. But that does not preclude people with a will and conviction to enforce ethical behavior.
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Of course there will always be obvious cases of unethical behaviour, but who decides the boundaries that determine what is ethical and why should someone even be allowed to decide them?
This directly leads to the commonly mentioned concept of "Taint", however, I could point out something I have mentioned before:
If someone kills somebody and steals their wallet and spends the money at a supermarket, then you get that money as change, are you really guilty of any fractional part of that murder? Of course not.
Anyone who receives the money, and knows of the deed, maybe yes they are, but how do you decide which a person is?
The bottom line is, that it is indeed giving someone power and I am an absolute believer that that power is unnecessary and bad for bitcoin and also ... "Power corrupts, absolute power corrupts absolutely"
Next you'll have the religious nut cases claiming that buying Harry Potter with bitcoins is evil and any address that does that should be marked as Tainted ...
Simply put, let those who wish to chase down stolen coins, do it to their hearts content and even involve the police if they wish to, but making it part of the monetary system, I personally could never agree to it.