Intent is in the brain and criminal trials do try to discover it.
Oscar Pistorius shot and killed his girlfriend. "I thought she was an intruder; I did not mean to hurt her," he said (paraphrase). The facts were not in doubt; the entire case hinged on whether the jury believed he was telling the truth.
I agree that there is no way to recover a passcode from the brain (outside of science fiction). But it seems like a court could rule on whether claims of forgetfulness are real.
There's a huge difference between shooting a person and forgetting a password.
Further, any random assortment of bits is potentially an encrypted volume. At least with a murder there is a body. With a "forgotten" password -- or a password you never had to begin with because there is no encrypted volume -- nothing bad has to happen. So it's far more likely to be abused to put people behind bars that "we know did it" but where the police or whoever can't get them on anything else. Like how mobsters often go to jail for tax evasion rather than the violent stuff.
Intent is a factor in almost all U.S. criminal prosecutions, even people who are being prosecuted for shoplifting and say they just forgot to pay.
In terms of the encrypted volume, law enforcement has to prove each step on its own. They can't seize the computing device until they prove it is actually likely to contain evidence relevant to the prosecution of a crime. And they can't ask a suspect for their passcode until they prove that there is actually an encrypted volume to be unlocked (this is probably easier than you think). And if the person says they forgot the password, law enforcement would have to prove that they are lying.
Courts already handle similar situations with contempt and perjury proceedings. Even though criminal contempt or perjury is usually secondary to the "main case," it has to be proven beyond a reasonable doubt just like any other crime.
That's why it's not "abuse." It's not like law enforcement can magically lower the bar for conviction by some special procedure. When Al Capone went to jail for tax evasion, he really had evaded taxes, and the government proved it beyond a reasonable doubt.
I'm sure Capone really had evaded taxes. But the idea that the government couldn't get him on anything besides tax evasion is pretty sad.
The idea that the police or prosecutor has to "prove" all this stuff is nice, but not in line with reality. Warrants get issued on suspicion all the time. There's not a pre-trial trial to determine in front of a jury if the suspected encrypted volume is in fact an encrypted volume.
The judge orders you to provide the password and if you don't you're held in contempt for as long as you don't. Which, if you don't know the password, could be the rest of your life.
That's why some in law enforcement might be tempted to invent an encrypted volume that doesn't exist. Because it short-circuits the normal judicial process. And when you know someone is guilty but the damn red tape gets in the way, it can be tempting to try and make things "right".
A warrant can be issued on suspicion, but once the judge or prosecutor tries to prosecute for contempt, they would need to prove beyond a reasonable doubt that it was actually an encrypted volume.
Oscar Pistorius shot and killed his girlfriend. "I thought she was an intruder; I did not mean to hurt her," he said (paraphrase). The facts were not in doubt; the entire case hinged on whether the jury believed he was telling the truth.
I agree that there is no way to recover a passcode from the brain (outside of science fiction). But it seems like a court could rule on whether claims of forgetfulness are real.