In the UK, for the most serious (indictable-only) crimes, then no. But you can ask the judge to end the trial after the prosecution case if no reasonable jury could convict, including if as a matter of law no crime has been committed.
The DAO was created with the intention to allocate its funds according to a certain voting scheme, with everyone's power determined by the number of tokens they held. But the program did not correctly implement this intention, and the DAO hack exploited the difference to bring the funds under control of the attacker. This most likely violated the Computer Fraud and Abuse Act, and was thus illegal.
Which is one of the issues with smart contracts. Yes, written contracts are the contract in the physical world. And sometimes people get outlawyered or just plain screw up and lose money because of circumstances that they didn't foresee. But when things come to court, there's still generally some oversight usually provided through the court system or mediators to put the brakes on clearly absurd and/or unfair results. Which is generally considered a positive thing.
Of course! Customs and other legal (based on moral) norms are basically the primary source of law or of its interpretation. Human systems based on rigid, or even utopian (that is totalitarian in practice) rules simply cannot handle the complexity of the real world. The system may seem good and functional at first but with the first problem which would because of the nature of complexity and chaotic system dynamics of human interactions inevitably happen, the system would crash (or in this case, get forked) since it would not offer any flexibility.
Without getting too abstract, even traffic lights or zebras, from the perspective of a pedesetrian, (as an example of a simple system) would be a horrendous and extremely time consuming experience if its rules were enforced by the letter. Imagine if you could >only< pass the road accross the zebras...
Human made systems need to be imperfect and the rules need to be flexible or the system will fail.
As I understand it, the DAO website explicitly stated that the code of the contract superseded any written or stated intent. Basically: The code is the law.
The actual law is the law, and contract law (and criminal law i.e. regarding fraud) states that the intent does matter. The DAO website doesn't make legislation - the code may specify the rules about which transactions the Ethereum system will approve, but in the real world the actual laws matter and they will determine whether some people will have their stuff taken away, their movement restricted, or be forced to do some transactions in the Ethereum system.
But the question that is to be debated is, was the intention of the DAO too follow the code of the contract EVEN IF it had a bug.
There is an argument to make that, given that "the code is law" was plastered all over the DAO, that being hacked and having all their money stolen, was explicitly allowed.
Advertisers are occasionally held to some sort of legal commitment with respect to statements made in their ads. The "hackers" in this case might claim they wouldn't have invested their money if they hadn't believed the ad...
The "Computer Fraud and Abuse Act" applies to the US.
What if the hacker lives somewhere else? Then that law does not apply to him, and the action was not illegal.
I would assume all allied countries have similar laws and therefore share extradition treaties.
Even countries that don't have shared extradition treaties don't always ignore criminals within their borders, even if the criminal activity is occurring outside.
