You're totally right, but "we suspect there's a hidden volume" and "this machine is clearly locked, unlock it" are two very different situations. The prosecutio

You're totally right, but "we suspect there's a hidden volume" and "this machine is clearly locked, unlock it" are two very different situations. The prosecution and even the judge might be convinced that it's extremely likely that you have a hidden volume, but that's not the same as compelling you to unlock a phone. It's the difference between "you are ordered to open the secret safe we suspect exists."