Pocketstar Put the duress password near the phone, like the insides of a phone sleeve.
In the US:
Should this be recommended? It seems to me to just be increasing risk. I mean, it's a stronger argument against destruction of evidence than giving them the duress password directly but it seems to go past the smart and secure line with a little more secure but less smart.
If you want to avoid significant complications with still a very high chance of protecting your data, I would just not use the duress pin. I mean maybe you could set it to 1234.
But any duress pin involvement against law enforcement seems to be making things more complicated for you with little reward. You already are in a country with no key disclosure laws, maybe enjoy them?
If you want to maximally protect your data and don't care about complications, then using the duress pin is safer.
If the data is obtained from your phone illegally, it can't be used in court. The time to fight is in court, not at the scene. Comply with the person with a gun, but don't talk (unless they are acting illegally, there's always edge cases).
One thing to note is that talking to the police can never help you in court, it can only be used against you. At least, according to this famous video. The only thing talking could get you is the police leaving you alone at the scene, but if they suspect you they're not going to leave you alone anyway, and if they're corrupt (like many police), they will just use what you said against you anyway even if you are completely innocent.
Pocketstar Precautions;
An additional precaution. You should not keep sensitive data on your phone particularly when crossing borders. Create a Proton account over Tor and only access it over Tor. Memorize the credentials. Don't put the credentials in your PW manager. Store your data in proton drive and only access it from the Tor browser. Still, do not say anything and don't disclose any credentials, do not let them search the phone just because you data is in the cloud and safe and you think that will let you through easier or get then to stop bothering you. Because they can plant evidence as Pocketstar said. Also due to the way SSDs work, data is not deleted, deleted data is protected through encryption. You could also backup your Signal and delete it.
These are not precautions so you can then give them the password to avoid hassle. They are defense in depth on top of not disclosing keys. Your job is protecting your data and avoiding punishment by a court, not getting out of trouble in the eyes of the cops. Your job is to avoid escalation at the scene, though. They are not judges, they don't care if you're innocent.
At a regular traffic stop, you can answer their questions and they maybe won't give you a ticket. Or you can only provide the required information, license, registration, proof of insurance, and weapons in car depending on state. And then don't talk. You will likely get a ticket if you don't answer because it annoys them. You should definitely comply with any orders—the time to fight is in court, not on the road.
But they won't get anything else. And you wont have weakened your case to fight the ticket in court. Because nothing you say at the scene can help you in court. It can only hurt you.
For court, it does seem stronger to invoke the 5th amendment and then stay silent than staying silent completely.