I can't be the only person who has thought of this.
For now. It doesn't seem like an especially natural fit. Regardless of the merits of being able to compelled to turn over your password, relying on labored interpretation of laws is not a good idea: 14th amendment was always a very shaky basis for abortion rights, as the 2nd is a very shaky one for personal gun rights.
Nitpick, but that's only if you have biometric authentication configured in the first place, which you aren't compelled to do.
I'm sure they will claim its a crime if you set it up that way, but is it?
They can already legally compel you to provide your fingerprint. You can't avoid that, you'll get put in jail. Do you have to tell them "don't do that with my phone, it will reset everything if you do that".
It might work if your fingerprint was used while you were unconscious, but any solution that starts with "setup a trigger that wipes a device" is already on shaky grounds.
There are videos on youtube where the lawyers tell you what your rights are at traffic stops, also there are ones that talk about the different rules when coming through immigration. These can be painful to see when they show the ones where cops ignore limits.
So at the border, they tell you that you are legally required to provide your finger print, you do that, and don't say a word. I'm sure it will be a bad day for you, regardless of how it works out after years of litigation on whether it is your duty to tell them how NOT to unlock your device.
It isn't on shaky grounds: you protect your private device from everyone, not just from some "law enforcement". If you want to protect your private device from any party (e.g. thieves, trivially), it will also be protected against law enforcement agents as a side effect.
And remember that the context here is you explaining your digital booby trap to a judge who thinks you might have deliberately destroyed evidence.
"Wipe the data after a number of failed logon attempts".
I understand that this does not fit completely with the "in front of law enforcement" idea, but it opposes your «any solution that starts with "setup a trigger that wipes a device" [would be] already on shaky grounds»: we can very legitimately setup triggers that wipe devices in the possibility that the device falls into random hands.
https://www.nytimes.com/2026/07/28/us/duress-password-phone-...
Intentionally giving a duress PIN which you know will wipe evidence - information you were just asked for by some law enforcement - just robs you of more of years and money. The law is lopsided and gives some more power than others. There's no point debating why it's like that, try to change the law before you break it or find ways to not need to break it at all.
The law here is destruction of evidence. The guy destroyed evidence by giving the wrong password to the police. If the police had destroyed it of their own accord, he'd be free. If the duress PIN was 1234 and the police just tried it, he'd be free.
There are all sorts of situations where people go free despite the wistful desires of prosecutors, due to the details of what happened and what the law actually says.
Of course it should be code. More specifically, it should be completely deterministic.
This idea that judges/courts can interpret the law however they feel like it in each individual case is what gives power to dictatorships. Then there is no way to know what is legal vs not, each scenario is different and the courts will inevitably choose what favors them. So yes, ideally, law should absolutely be "code" (deterministic).
(Common sense tells me that the accusation might make sense both in cases in which the accused knows about a crime and in cases in which the accused knows about a police investigation, even in the absence of a crime, but deleting nude photographs to stop a customs officer from seeing them, for a random example, would that be a crime?)
"You dumbass! You use my thumb to trigger duress mode! Don't you know thumb is always wipe, and PIN is always unlock? Moron!"