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One disadvantage of the Bitcoin/Ethereum architectures is that one cannot give permission to receive a currency transaction first.

A common strategy of hackers seems to be to distribute stolen digital currencies among many addresses of non-participating actors, therefore losing money, but obscuring their own identity.

If a bank robber came to your door and offered you a share of money, you wouldn't take it either, especially if this transaction is public.

Even though several billion dollars of cryptocurrency (compare with hundreds of billions of dollars) have already been stolen, my guess is that taking these coins out of circulation wouldn't affect the system much.

If that doesn't happen, everyone participating in cryptocurrency might become more and more legally liable.

"What color are your bits?": https://ansuz.sooke.bc.ca/entry/23

"Treasury designates [...] digital currency addresses": https://home.treasury.gov/news/press-releases/sm556