It matters a lot whether she is a US citizen or not.

If she’s a citizen, then she can shut up / lawyer up. She has a fifth amendment right to not divulge a phone or computer password, code, pin, or whatever. CBP can detain her for up to several hours, but at the end they have to either charge her or release her into the country.

If she’s not a citizen, then things are a lot tougher. She still has constitutional rights, including the fifth amendment. But CBP has a lot of leverage, because they can rule her inadmissable. Once that happens once, then it can become really hard to get readmitted later, because this “strike” is on your record.

The main thing that is tripping up green cats holders at the border currently is old criminal records. That DUI or marijuana or shoplifting charge or conviction from 20 years ago is often not enough dirt to get an LPR deported, but it is enough dirt to deny readmission if they happen to leave voluntarily.

Encrypted data channels can still be vulnerable to man in the middle attacks. Like when you connect to an unknown host with SSH, and the client pops up a big warning.

In this case, ICE or whomever sets up a “valid” cell tower that your phone connects to, and they (law enforcement) route your packets onto the rest of the Internet. They can decrypt the 5G data, and see all of the IP headers. They can’t necessarily read the TLS traffic, such as https. But most important of all, they can log all of the IMEIs that connect, which effectively gives them a database of all of the protestors.

The use of Stingray by US law enforcement has been challenged on grounds that the law enforcement agencies have no spectrum license. Those challenges seem not to have found success.

On the other hand, prisons in the US have been stopped from operating cell phone jammers on prison grounds, on the same complaint of no spectrum license.

The wrinkle in this case is that the thumb print giver was in parole. The conditions of parole stated that failure to divulge phone pass codes on phones could result in arrest and phone seizure “pending further investigation”. The parole conditions didn’t say anything about forcible thumb print taking.

So the logic here seems to be:

• If he had agreed to unlock the phone then the result would be the same.
• If he refused to unlock the phone, that is a legitimate grounds for arrest. Fingerprinting is a routine part of being arrested, so there’s really no harm if it’s done on a phone in a patrol car. Either way, the result would end up about the same.

Especially talk to FSF if this “well known debugging tool” is a part of the GNU project, as FSF has the power and standing to enforce the copyrights on GNU software.

Ctrl+alt+delete was a separate interrupt line direct from the keyboard. That is, when you pressed the three keys, the interrupt signal was asserted, causing the CPU to jump to the interrupt service routine, which should be in the source code package.