If you're a citizen, you'll likely have less scrutiny. For an actual tip, disable biometrics on your phone. Apparently, they can use your biometrics to unlock your phone without a warrant, but they can't compel you to give your pin code.

If I had the option, I would wipe me device before crossing the border. If not, make sure it is powered off and biometrics are disabled when crossing.

And if they take it from you, throw it in a woodchipper. It is no longer a trustworthy device.

Hey, US citizen here who just re-entered the USA thru LAX.

In short, I did nothing abnormal aside from use the CBP app to generate a QR code to speed up immigration. Turns out they weren't doing QR codes or global entry or anything at LAX. So all US citizens were in a very long line with only 1 TSA agent processing people.

So I would prepare for a long queue. But Im a US citizen so that makes a big difference in your level of scrutiny.

I entered the US from Mexico a couple months ago. They asked if I had any produce. I said no. They said have a nice day.

When they ask, say you decline to use AI to look at your picture, then expect some snark from the agent.

Max paranoia: Backup your data and apps to a fully encrypted data source you trust. I.e. seedvault.. optionally you can practice restoring a backup on another phone .. a untested backup is just hope. And if your brave, factory reset.. once you arrive and are happy and safe, restore the backup

Reasonable: Prepare a second travel only phone: taxi apps, voip, travel email, secondary im

In the airplane-

Disable biometric unlock unless you have multifactor already (gos)

Turn off your phone before landing, and only turn it on after clearing customs. If your phone leaves your custody at any point then it's compromised and don't turn it on or login.

Be polite, respectful, and efficient in the airport.

Update:

My mom and older brother reentered the US with no issues

They didnt even check passport, its just all facial recognition now.

Didn't see this post till now. Might not be relevent anymore. Anyways:

Funny enough, my mom and my older brother kinda just went to China without any like phone wipes or anything¹, they're not even concerned at all. Naturalized Citizens, originally born in China.

(¹not that I suggest you do the same)

I'll post an update in about like 2 weeks (like around 20 of May)

I heard my aunts in the US, also Naturalized Citizens, also just go on bussiness as usual...

I probably would not wanna leave if on Green Card, unless you wanna like leave permanently. Either that or stay till you get citizensip, that's my advice for non-citizens.

I have not heard a widespread detainment issue... a lot of ethnic Chinese in my parents social circle apparantly cross the border just fine... some on Green Cards...