Issuing 'burner phones' and laptops to staff visiting countries such as China or the USA is now SOP for many companies handling sensitive data, including mine.
Don't think this isn't unusual.
A couple weeks before your trip, factory reset whatever burner phone you're planning on using and swap your SIM card over. Install a few basic apps you wouldn't mind them looking through. Enable hotspot/tethering, and connect your other phone via Wi-Fi.
For a couple of weeks, use the burner as much as you can with what is available on it. When you're driving, us the maps app for GPS. Make and receive some calls, ignore some spam calls. Read the news. Get a few inane text messages conversations going, etc.
When you travel, leave your regular phone at home and take the burner. When it's searched at the border, it has enough activity to pass most initial smell tests. If asked, you dropped your other phone and didn't have time to get it fixed before your trip, this is one a friend lent you.
This has worked for me. Never _actually_ into anything illegal, but just apparently had a suspicious vibe about me or something because every time I crossed the border into or out of the country I was spending 4-5 hours getting searched. Didn't need someone going through my entire life going back decades every time--once was enough.
Believe it or not, due process still generally exists and most people still benefit from taking precautions to protect themselves. That’s not to imply that things are great or that we aren’t in a time of declining civil liberties.
Seriously, there is something wrong with privacy doomers.
This comes across as fearmongering to keep people from protecting themselves.
If you get charged with a crime, things are very different.
There is no court at the border. If the agent decides you're going to jail, you're going to jail. The decision may be reversed/corrected after, but it's still going to be a big, expensive problem for you and you _are_ going to be detained for a time.
Not to mention walking up with an empty phone and telling the agent to "fuck off" when they ask about it sure sounds eerily similar to the facts of the case in the linked article. I'd wager that's a good way to land an obstruction charge.
For the second part, having an empty phone is not a crime, and being arrested for this would be a major scandal. The tech press and political outlets would be all over it. It’s generally a good idea to avoid directly antagonizing border guards, though.