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.