I think it's enough to shut down you phone. Then it needs a pin, and you're entitled to not give that over, I believe. So you should be safe, apart from some kind of rubber-hose cryptanalysis.
> So you should be safe, apart from some kind of rubber-hose cryptanalysis.
There are vendors that sell the technology to adversarially access phone data, the "Before First Unlock" is the safest state a phone can be, but it's not infallible. The safest option is to have a burner or factory-reset phone with nothing on it, even if the hack succeeds.
> Then it needs a pin
A compromise to this is that many phones have a "lockdown" mode, where it isn't fully off but refuses to accept biometrics until a code/pattern is used to bring it to a more day-to-day mode.
It's less-secure than being fully off, but it also means if you do need to access your phone you can do so more-quickly.
If you don't give a pin, they can seize your devices (Andrew Tate on his 1st visit to Florida said that he refused to give pin and they seized phone and laptop)
If you’re a U.S. citizen: CBP cannot deny you entry to the United States merely because you refuse to unlock the phone. If you’re a non-citizen seeking admission: refusal is much riskier.
The important wrinkle is that CBP’s published policy expressly guarantees that a person being admitted as a U.S. citizen won’t be denied entry solely because CBP couldn’t inspect the device. It doesn’t give lawful permanent resident (green card holders) that same explicit statement. Instead, it says refusal by a “foreign national” can be considered in an admissibility determination.
That’s probably why they’ve been pushing the MPC app heavily.