|"You do not have to say anything, but it may harm your defence if you do not mention when questioned something which you later rely on in court. Anything you do say may be given in evidence." - Right to Silence (UK)|
When I retired from police service, I had spent a third of my life working for the LAPD. One of the questions that someone with my resume will eventually face is the balance of case types worked, the implication being that I would have mostly worked for the prosecution of criminal defendants. But, in Los Angeles County, there's an over 90% plea rate. In reality, I worked on the major criminal cases about 50% of the time, with the remainder working in the defence of the my self-insured city. I've also worked in the defence of officers falsely accused of perjury (People v Abdullah) and have donated a lot of time for case review in support of Innocence Project type cases.
If you're an American, you will be more familiar with the Miranda warning than the warning shown above from the UK. But, I think the Miranda warning, and the 5th Amendment in general, is setting people up for failure in successfully defending themselves in court (assuming they're innocent of all charges). Here's what I mean.
Americans generally believe that it's up to the State to prove guilt. Whilst this is true in theory, there are so many stories about innocent people pleading guilty to charges based on a "risk assessment" that they make about their potential to succeed at trial. The Prosecution has their theory of a case. The State's investigative might has been focussed on the Prosecution's theory in the collection of evidence. They're not necessarily concerned with the collection of alibi evidence for you. They may stumble upon potentially exculpatory evidence, but that's not their job - it's yours.
This is where I think the UK's standard admonition is more honest. Sure, you have the Right to Silence. But, by remaining silent, you may actually harm your defence.
If you are innocent, you know where you've been, with whom you've associated during the time in question, places you've visited, and etc. Your defence team must begin it's own evidence collection process. Your movements throughout the day all leave traces - the store, the gas station, the coffee shop, highway tolls, and etc. There's very little about one's life these days that isn't tracked or recorded. In addition to CCTV video of you going about your day, your phone has likely recorded even more details about where you've been and what you've been doing. Now, there's even the personal home assistants like Alexa and Siri that can serve as a witness to your movements.
All of this data must be preserved. However, the average person doesn't have the resources or the know-how to collect and preserve digital evidence properly. Some items, like cell tower logs, may require a warrant to acquire. You must have a capable and aggressive lawyer working on this for you.
I'm here to help. I've seen all sides of this and have been working on standards for digital evidence collection and processing for well over a decade. I've taught classes to public and private audiences on this as well (click here for more info).
Yes, in the US we have the presumption of innocence. But, the best defense is a good offense. You must go on the offense and collect the evidence that proves your innocence. The evidence shows that it will harm your defence if you don't.