I really like the idea of a hacked hard drive or phone which generates a never-ending series of files containing terabytes of random data. I bet any given boarder crossing will only have the ability to scan two devices at a time, so bring a couple and you can probably shut down everything as they scramble to figure out what to do when their local storage fills up.
I realise that this is not the exact argument that i was originally making, but technical people are unlikely to rethink technical solutions without them understanding the technical barriers that limit a "solution's" effectiveness.
Most hard drives (and presumably SSDs) contain embedded microcontrollers to handle translation between the various protocol levels (USB, SATA, etc) and the raw data on the platters/FLASH cells, often running i/o drivers on top of some microcontroller-specific RTOS.
So ... surely the ideal technique would be to write a driver for the RTOS that generates a stream of data on the fly that looks like an ExFAT filesystem full of directories and email folder hierarchies containing Lorem Ipsum text? That way, it keeps feeding an unending supply of junk back to the imaging hardware (which probably isn't anything as high level/simple as "plug into a PC, mount it, and copy everything"). Yet if they open up the case and look inside, they'll see a genuine hard drive with genuine platters.
If I had to do this, I would indeed make a faked Nimbus 100TB SSD drive, but it would also be super slow and glitchy. Spit out the proper meta data, then slow random noise presented as glitchy virtual sectors. Done deal. They've surely imaged glitchy drives before. They aren't rare.
How many drives can they image at a time, and how long does it take? How many drives can they not image because yours is taking so long? That's what I would attack.
I'm wondering if it's not gonna be another 'good' reason to keep anyone they want to mess with for days. Oh sorry we can't read m2 disks we have to call the guy from the place that has the only converter. We'll keep you warm in the mean time. You didn't have a flight connection or a lawyer you wanted to call, right?
Based on prior stories I've read - trolling pissed off people with any form of Authority could end up very very badly for anyone doing this.
Aside from them just out and out confiscating any electronic device they like, they could detain you for a long period of time, they could put you on no-Fly lists (and then good luck ever flying into/within the US again), they could put you on extended screening lists (and so, every time you fly then on - again, kiss goodbye every electronic device you posess every time you travel, again). If you're a foreign national, or even if you look vaguely foreign, you might find yourself deported/denied entry/locked up for a while during the deportation process.
That's before they even get motivated enough to be malicious - I'm sure if they wanted, they could gin up enough of a case of "obstruction" or "wasting police time" if they can find any evidence (or even anything that looks like it could be hint of intention, like posting on HN), which even if it never goes to trial can still make your life a living hell, cost you your job, and a huge amount of money defending.
Or maybe they're just people who want to protect the country they live in? You can't just view everyone who disagrees with you politically as a drooling idiot.
That being said, you are of course correct.