I think stuff like that would be up to the jury to decide. If I was on that jury I definitely wouldn’t consider just having a duress password to imply intent of “knowingly preventing the Government to take property into its custody”, especially since GrapheneOS doesn’t really mention state actors in its FAQ. It would be reasonable for him to claim that he enabled this feature to protect himself from illegal searches or kidnapping, and accidentally gave the wrong answer to the cops.

But reading the OP interview it seems to me that he is almost admitting that he wiped the phone intentionally, tipping the scales significantly. Is it “beyond reasonable doubt” that he intentionally gave the duress password now? Maybe.