Question: (Inspired by [Can a lawyer subject the court to a (temporary) ruse for a legitimate purpose?](https://law.stackexchange.com/questions/36934/can-a-lawyer-subject-the-court-to-a-temporary-ruse-for-a-legitimate-purpose))

Under which circumstances are witnesses asked to identify people present (in particular defendants) in the courtroom?

* In which jurisdictions is this a thing? (I know it happens in the US; what about the UK, etc?)
* Are there rules mandating it (either local court rules, statutes, or jurisprudence), or is it something the parties may choose to do or not? If the parties choose, why would they do or not do it?

Answer: 
[canada](/questions/tagged/canada "show questions tagged 'canada'")[criminal-law](/questions/tagged/criminal-law "show questions tagged 'criminal-law'")

In Canada, this is called "in-[dock](https://justice.org.uk/in-the-dock/)" identification and, while not prohibited, it is recognized to have very little probative value. It has "particular frailties over and above the normal frailties attaching to identification evidence" and "adds little" (*R. v. Izzard* (1990), [54 CCC (3d) 252](https://canlii.ca/t/gd876), pp. 255-56 (Ont C.A.); *R. v. F.A.* (2004), [183 CCC (3d) 518, para. 47](https://canlii.ca/t/1grgd#par47) (Ont. C.A.)).
[new-south-wales](/questions/tagged/new-south-wales "show questions tagged 'new-south-wales'") [australia](/questions/tagged/australia "show questions tagged 'australia'")

**There are strict limits on *[visual identification evidence](https://www.judcom.nsw.gov.au/publications/benchbks/criminal/identification_evidence-visual_forms.html)***

This comes from Part 3.9 of the Evidence Act which is based on a uniform law across all states, territories, and the Commonwealth.

*Visual identification evidence* (including in-dock identification) is permitted only when it was part of a properly conducted police line-up, it was reasonable in the circumstances that there was no line-up, or where the defendant refused to participate in the line up after receiving legal advice.

Even when it is admissible, the judge must instruct the jury of its low probative value and advice them that they must consider such evidence cautiously before assigning it any weight.

Exceptions apply when the defendant’s identity is not an issue at trial, or when the defendant is previously well known to the witness.