It seems like a bad idea to store anything incriminating on your local hard drive. Why not keep your encrypted files on a flash drive? If the police show up destroy the flash drive using a hammer, ensuring that the flash memory chip is thoroughly pulverized and completely unreadable. Likewise, if you are going to be using the internet for devious purposes drive around and use a neighbor's open wireless network access…
But my goal is not to be a smart criminal. My goal is to have a right to privacy to my own stuff.
That said, I don't see why the well-established precedents of opening locked doors and safes shouldn't apply to computers. If you subpoena my safe, I have to open it for you. Otherwise, I certainly won't.