These are good things, by the way, if you want btc to be treated as meaningful commercial currency.
What good is seizing a computer if the whole drive has been encrypted. The password? "Password123". That doesn't work? Hmm I must have forgotten it.
The is before we even get to fun stuff like deniable encryption.
http://www.truecrypt.org/docs/plausible-deniability
Oh the Gigabytes of random data on the drive? I always write the drive with random data after a format to make recovery impossible. Feel free to try and prove this random sequence of bits is an encrypted partition and not just a random sequence of bits.
Your're right that someone this prepared and smart could make finding and liquidating asset X a challenge, but how many people do you think are that prepared? What subset of those people would ever be in the situation of not honoring their obligations in the first place such that hiding assets is necessary?
It's not "getting to the actual coins and being able to liquidate them instantly" that is the only pressure point for a motivated creditor versus an extremely well-prepared debtor. You might be able to keep USD buried in your yard that a US Marshal wont find on the first 10 trips to your house. But eventually that money comes out of the ground to pay for stuff, like lawyers. The creditor's goal is learning enough to justify a suspicion that there is probably wealth somewhere, and applying pressure elsewhere to convince you to cough it up. Simply "forgetting" the details and records to explain where all your assets went isn't good enough, may land you in jail for perjury, and is enough (by itself) to lose a right to a last-resort bankruptcy discharge, for instance.
None of this stuff is worth worrying about if we're talking about small potatoes debt. Just don't screw over real large stakes investors and lenders and expect to live happily and wealthily ever after because you think you're long in an invisible asset.