How would this work though? You have 4m worth of blacklisted bitcoins. What happens if you go to a legitimate store, like NameCheap, and buy a domain using those bitcoins. You're going to add NameCheap to the blacklist now, because these coins went through them?
Well, you could say NameCheap wouldn't accept those coins in the first place, but can you really expect every store and person to be using this list?
What happens if you take those 4m worth of bitcoins, send 3m to your own wallets, and distribute 1m to random wallets of strangers? How do you know which wallets to blacklist? All of them? You're just going to put tens of thousands of people in the dark, and say their bitcoins are now worthless and blacklisted, because they received a random payment?
Hmm, I didn't realize you could send money to people without their consent. That would make blacklisting more difficult. But if receiving the bitcoins was indeed unintentional on their behalf, you could just temporarily blacklist them until they returned the stolen bitcoins to the original owner.
In theory this could lead to attacks where small amounts of stolen bitcoins are continually deposited in victims' accounts, but that could be avoided if the exchanges themselves enforced the blacklist and refused to process transactions from blacklisted accounts (except back to the theft victim).
> Well, you could say NameCheap wouldn't accept those coins in the first place, but can you really expect every store and person to be using this list?
It would certainly require a cultural shift in bitcoin use, yes. I just find it funny that the entire transaction history is public record, yet bitcoins can still be stolen!
> I didn't realize you could send money to people without their consent.
I think the point of blacklisting would mean that miners wouldn't include transactions from those addresses in blocks. Once the transaction is in a block then there's not much that can be done, so blacklisting will require cooperation among a majority of miners.
Well, you could say NameCheap wouldn't accept those coins in the first place, but can you really expect every store and person to be using this list?
What happens if you take those 4m worth of bitcoins, send 3m to your own wallets, and distribute 1m to random wallets of strangers? How do you know which wallets to blacklist? All of them? You're just going to put tens of thousands of people in the dark, and say their bitcoins are now worthless and blacklisted, because they received a random payment?