The $5 wrench isn't about breaking encryption. It's about breaking will power. If they achieve their goals great for them. If not they proved the second volume either didn't actually exist or your will power was stronger than the $5 wrench. Either way they're probably way more happy with the outcome than you would be.

As long as the border your crossing doesn't respect the 4th Amendment, the best approach is to not carry anything incriminating across it, nor anything that may make you suspicious.