That's really what's missing from web3: the concept of what a reasonable person [1] would believe - not a code-based contract.
[1] https://www.courthouselibrary.ca/how-we-can-help/our-legal-k...
Meanwhile in Japan, there was a crazy sentence for a crime of using a crypto-currency that has been stolen. Not the real criminal responsible of the theft, but some random idiots who think investing on crypto-currency was a good idea and purchased the token that was a part of stolen token.
I bet these idiots has never run full-node on the computer he owns. He just relies on some SaaS wallet service by somebody else.
I guess ignorance is a crime.
However, the same defense does not protect against confiscation; just criminal liability.
Former is what "ignorance of the law is not a valid defence" applies to. Latter can be valid, and particularly in this case I'd find it hard to imagine that those affected by the dusting attack would be found guilty of violating sanctions.
Edit: Actually I have to partially walk that back. It's fairly buried in the comments on the other article, but it looks like the GitHub bans were a lot more limited than that. On the other hand, I could still see an exchange taking such an approach, so I'm going to leave this comment because I think the point is still valid.
I really think the OFAC regime made a mistake here. They overplayed their hands and this will result in a bunch of debate and court activity, which may reduce their power in the end. I would have started mass-blacklisting frequent users of Tornado rather than the contracts themselves, and certainly not by-default made Americans criminals who receive Tornado funds. That is clearly unenforceable and will put a magnifying glass on this issue.
There exist in our society things that the state is actually unable to completely prohibit, prostitution and cocaine principally among them.
It's possible that cryptocurrencies also fall into this category.
The state's power to ban things is not without practical limits and constraints.
this is fundamentally a social technology, and can be built on top of what exists. it's nearly impossible to bridge the gap from systems built on human judgment (trusted) -> impersonal contractual absolutism (trustless), but the reverse is a simple matter of opting in. you only have to allow others to have rights over your property, and interact with others who do the same.
this is more or less what i would expect to happen over the long term; most people prefer safety and convenience over shouldering the entire burden of security and awareness for every financial transaction. it's vitally important that the option remains available, though.
If this hadn't happened to such high profile people, someone in court might be trying to say things like "look, I know my address is on the sanctioned list for money laundering but that's because someone I didn't know paid me", and the judge is going to be skeptical and say "I don't understand this blockchain stuff, but the software from <trusted sanctions partner> says you are guilty of sanctions violations."
Law and sanctions are not "reasonable persons". It's not up for interpretations.