If this becomes a reality and the powers that be actually care about doing things more or less right then I imagine they would write an easy to use piece of software that border agents can run which automates checks for all those things and many more.

>How many border protection agents look into your /etc/fstab and know fdisk, mount and cryptsetup?

They don't need to. Microsoft and other companies have been providing software on bootable CDs and USB keys to do quick 'security' audits of PCs for years to various police forces. I'd be extremely surprised if detecting encrypted/hidden partitions wasn't a common feature.

it would be very useful to know exactly what tools and techniques the border agents are using.

Is there software that detect HDDs that are disabled via BIOS? Do the border agents reset the BIOS? Are they looking at individual files and encrypted archives?

I don't know the capabilities. I'm sure the best ones are kept secret obviously. One MS tool was leaked online but turned out to be nothing special: http://www.microsoft.com/industry/government/solutions/cofee...

It's underkill, almost. My partitions are already encrypted, all I need is to save + trash + restore the physical LUKS blocks. I don't need to reconfigure my system or do anything differently when I'm not travelling. It's a low-mod hack that I can even explain to the customs people: I'm afraid someone might try to steal my online banking or financial credentials or something, so I chose to disable my personal partitions temporarily instead of being vulnerable to being threatened. I can't be made to move my money to some criminal's account if I can't access mine.