What is the test for cautionary witness instruction in a criminal case?

A cautionary witness instruction is not limited to accomplices or those who fit the traditional definition of an unsavoury witness but may be required for witnesses found not credible or unreliable for other reasons. In determining whether to give some form of cautionary warning, the trial judge should focus on the facts that are stated to make the witness or the evidence unreliable or not credible, rather than asking whether a particular category of witness or evidence is at issue (see R v. Fatunmbi, 2014 MBCA 53, at para. 34).