It takes a while for case law to catch up to technology. I don’t think it’s going too far out on a limb to say it’s not settled law yet.
Here is a 2021 case that the Supreme Court declined to rule on:
I knew there was a reason I didn’t use the fingerprint feature on mine!
Actually I didn’t think it wise to have my phone “know” my fingerprint because where is it stored and who has access and what happens if I lose the phone etc.?
Just thinking in the general case, wouldn’t the cops be tempted to look around just to find stuff to help their case? Not just this DUI, but any kind of criminal matter. If someone is picked up for attempted murder, they’d have to do the same unlock to get the numbers. I would think the cops would love to snoop the phone to find out potential suspects and possible evidence. Even if they couldn’t present the phone evidence in court, I would imagine it would give them a huge leg up in figuring what to look at to solve the case. I can’t really imagine that professional integrity is so high in the police force that they wouldn’t illegally snoop around in the phone if they had a chance.
Just because there is temptation doesn’t mean you act on it. There is a temptation to take that stack of money you find. You don’t because it’s wrong and it’s not worth it. There is no case that’s more important than my family. My family relies on my paycheck no on me solving a particular case. Some dumb officers have gotten into trouble by snooping around where they know they need a warrant. I’m not that dumb. The pressure to solve cases as shown on tv is way overblown. Many cases don’t get solved. There will be 3 new ones tomorrow.
In the theoretical attempted murder case you cite we would get a warrant and let an expert go through the phone rather than haphazardly flip through and hope we find something. For the most part what we are looking for won’t be on the phone. Location data and call logs we get from the phone company with a warrant or grand jury subpoena.
I have a vague memory that this was discussed here on the SDMB before and the answer was the 5th amendment only protects what is in your head. The government cannot make you say something that might incriminate you. Pretty much all else is fair game (assuming the government has an appropriate warrant).
For instance, you do not have to tell the police the combination to your safe but if a physical key opens it they can make you give them that key (or just take it from you). Same as they can make you open your trunk even if you do not want to because that is where you put the body.
Read the article. That’s not what the appeals court said and the Supreme Court refused to hear it. It is not settled law.
I did read it and it noted the decisions in the courts is split. In New Jersey it seems they can compel you to give your passcode. In California they cannot.
I found where I got my example above:
According to such courts, the passcodes themselves are of minimal testimonial value, and therefore can be compelled if their existence, possession and authentication are “foregone conclusions.” This rationale improperly extends a narrowly drawn exception in Fifth Amendment “act of production” doctrine to encompass nearly every person who owns a cellphone. Critics of that analysis cite to Justice Stevens’ metaphor that the government can require you to surrender the key to a locked safe but cannot force you to say its combination to argue that requiring a person to disclose their passcode is a testimonial act that cannot be compelled. SOURCE
Further:
In Doe v. United States , the Supreme Court held that a combination to a wall safe is considered testimonial because recalling the passcode forces a defendant to reveal a product of his mind. In 2018, the United States District Court for the District of Columbia found the distinction between a numerical passcode that would only be known and entered as a product of a suspect’s mind, and a fingerprint passcode which does not require any mental effort of the suspect dispositive in its determination that compulsion of a fingerprint passcode would not implicate the suspect’s Fifth Amendment right against self-incrimination. SOURCE
That’s what happened with my step dad. He got arrested for DUI and the Kenosha county sherrifs asked him if he was sure he wanted to make that call. They all knew my mom as she was a volunteer for the county’s victims services and adult survivors of domestic abuse programs. And that she had successfully left him and had a restraining order in place.
That’s also how we got to hear them tell the story of his most famous line “you can’t arrest me, I’m a motherfuckng minister!!” So, silver linings I guess 
You can always ask the police to look up the firm by name.
~Max
OK but suppose I am arrested and I say, “I want to call my attorney.” You may know it’s useless at that moment and that you won’t be questioning me immediately (I don’t know that) but I can’t believe you wouldn’t let me if for no other reason you wouldn’t want to be on the stand and my attorney says, “Officer Loach. Isn’t it true that after the arrest, you refused to allow my client to call me for representation?”
There are plenty of YouTube videos of drunk driver arrests where the officers tell the driver that they can call the attorney later. Saying “I want to call my attorney” isn’t a magical enchantment that requires immediate action.
@Loach said the suspect will get a chance to call an attorney, only later. How is that a problem?
I never said it was a problem. My question was what happens if you do not have a phone number memorized.
You don’t have the right to see an attorney after you’re arrested. You have the right to see an attorney during questioning.
If they want to question you and you insist on seeing an attorney, then it’s in their interests to give you as many phone calls as you need. Otherwise, then your access to a phone depends on how long they feel like feeding and housing you without violating your right to a speedy trial.
Holding cell space is often limited, and there’s a steady stream of other offenders to process. Cops want to move this process along without unnecessary delay. It’s inconvenient for them to hold you too long. So if helping you find a good phone number helps move the process along, then they’ll help you do that.
As I mentioned above, the “speedy trial” constraint is generally taken to be 72 hours. So you could be locked up for 72 hours with no phone call and then released without being charged.
I was replying to @Saint_Cad who was suggesting it was a problem if they didn’t get an immediate phone number.
They absolutely can. Once you’re arrested, they’re going to hold you until trial. That’s the point of bail- you can put up enough money to essentially guarantee that if they turn you loose, that you’ll show up to your trial in order to recover it.
But if you can’t make bail for whatever reason, you’re going to sit in jail until your trial, because otherwise they can’t guarantee you’ll show up.
With DUI, the suspect has to make an on the spot decision about whether to consent or refuse the breath test at the station. When I was a public defender we would take turns being on call for those 2:00 a.m. arrests. We even had a beeper. The cop would give us a call (We got to know most of them pretty well) and they’d put the suspect on for a private chat.
Ah…sorry. I thought the board said you had replied to me.
My mistake. Carry on.
My state doesn’t do bail. Just wanted to muddy up the water a bit.
So I leave jail after processing giving my word as a gentleman that I’ll return on a future date? Is that as effective as bail, or just more simple/efficient?
It’s a bit more complicated than this but I’ll give the simple version.
Most criminal charges will be put on a summons. The defendant gets released as soon as they are processed and given a court date.
A request for a warrant has to be approved by a judge. If the warrant is approved the defendant goes to jail. There is no bail. By law they must be seen by a superior court judge within 48 hours (usually less than 24). The judge determines if the defendant should remain in jail on pretrial detention, released with conditions like monitoring or released on their own recognizance. There is no bail involved.
It was an oversimplification to say we have no bail. Bail is still set for contempt of court/failure to appear. So if you don’t show up for your parking ticket you will have a warrant with bail. If you hit someone with a bat there will be no bail. I don’t make the laws.