I think this argument would be more compelling if instead, you pointed to the fact that they cannot prove that the hard drive contains anything at all. The prob

I think this argument would be more compelling if instead, you pointed to the fact that they cannot prove that the hard drive contains anything at all. The problem of deciding whether or not the hard drive is encrypted is equivalent to decrypting the hard drive. It's like the police showing up with a warrant to enter a house that they cannot prove exists, or that I am the owner, and then holding me in contempt for failing to open it. What if your hard drive was encrypted maliciously and then taken into evidence? Is it even possible to prove that this isn't the case?