If someone says I need a cab for after I rob a bank and you give them a ride after waiting then you’re almost certainly an accessory. If they flag a random cab off the street then not.

I think in most modern democracies you aren’t legally required to tell the police anything. Courts are a different case though.

As a suspect. At least in court, as a completely non-involved bystander you have no right of refusal to testify in most jurisdictions.

Not sure whether that extends to police questioning though.

It doesn’t extend to police questioning, i also pointed out it’s a different thing when you are in a court. For the police an innocent bystander can turn into a suspect real fast.

The English common law tradition has a crime called “misprision”. Misprision of treason is the felony of knowing someone has committed or is about to commit treason but failing to report it to the authorities.

It still exists in many jurisdictions, including the UK, the US (it is a federal crime under 18 U.S. Code § 2382, and also a state crime in most states), Australia, Canada, New Zealand and Ireland.

Related was the crime “misprision of felony”, which was failure to report a felony (historically treason was not classed as a felony, rather a separate more serious category of crime). Most common law jurisdictions have abolished it, in large part due to the abolition of the felony-misdemeanour distinction. However, in the US (which retains that distinction), it is a federal crime (18 U.S. Code § 4). However, apparently case law has narrowed that offence to require active concealment rather than merely passive failure to report (which was its original historical meaning)

Many of the jurisdictions which have abolished misprision of felony still have laws making it a crime not to report certain categories of crime, such as terrorism or child sexual abuse

> Then I think you're legally required to tell the truth here.

Or you can just not respond, at least in the US. https://en.wikipedia.org/wiki/Self-incrimination

That only applies if you're the defendant.

If you're the witness to a murder and you're subpoena'd to court and refuse to testify then you are committing contempt of court. There was a guy in Illinois who got 20 years (reduced to 6 on appeal) for refusing to testify in a murder.

https://illinoiscaselaw.com/clecourses/contempt-of-court-max...

Contempt of court usually has no boundaries on the punishment, nor any jury trials. A judge can just order you to be executed on the spot if you say, fall asleep in his courtroom. Sheriffs in Illinois have the same unbridled power over jail detainees.

i think in actual practice you will rarely get contempt for refusing to testify or taking the fifth for questions that could only tenuously implicate yourself in practice.

Usually if you let the prosecutor know up-front that you're not willing to cooperate they will tend to save themselves the hassle of trying. It can go wrong if they subpoena a belligerent witness, then they don't turn up on the day they're supposed to testify, and now the jury is empaneled and they start doing a dance where they demand the sheriff finds the witness, but then the clock runs out on holding the jury and it's a mistrial all round.

That guy needed a better lawyer. He could just have said "I don't remember. Can't say for sure" repeatedly

Yes, "I don't recall" is the oft-heard phrase in the witness stand. I don't remember the specifics of that case and why the guy decided to martyr himself.

I don't think it's necessarily self-incrimination to report a crime you witnessed, though I think it's dependent based on the time from when it occurred to the time of reporting.

Such laws exist in most countries. I'm not aware of any that provide such a right to business entities though.

Depending on the jurisdiction and the crime and the circumstances an act of omission (like ignoring a murder) would be suspicious and may get you charged with aiding and abetting.