I co-wrote a border search guide for EFF some years ago. I was very interested in finding clever technical approaches but I later ended up feeling that I hadn't given enough thought to the overall threat model questions (even though the guide did address them, perhaps even somewhat usefully). The big picture problem is that the agents performing the searches have an enormous amount of power in terms of potentially se…
That's the same problem with technical solutions to crime.
I come from a very dangerous city and I used to have a car that needed a PIN to work. You could turn then engine on and drive but after a minute if you didn't input the PIN it would turn off without warning and start blasting the alarm. The idea being that if the car was stolen the thief would be stranded not far from home unsure about what's happening. Great technical solution but it ignores that a lot of the time the car is stolen with you in it (in a kidnapping, for example). Having the car shutoff in the middle of a highway next to a panicking guy with a gun and trying to remember a PIN is not a situation you want to be in, so I just had the PIN number written down on the dashboard, which worked very well when I was eventually kidnapped and just pointed at the piece of paper with the number.