What is the test for caution respecting the right to silence?

Dambrot J., in R v. A.D., [2003] O.J. No. 4901 (S.C.), after considering the earlier authorities on this issue, offers a comprehensive test: The trigger for an expectation that the police will give a person being questioned a caution respecting the right to silence must be less than reasonable grounds to believe that the person committed an offence, but must surely be more than speculation, knowledge that other persons suspect that person, or even reliable information that … a person’s “background, relationship to the victim or the opportunity to commit the offence may warrant further inquiry” (at para. 75).

To cast the net wider than this is to overemphasize an individual’s right to silence at the cost of stifling legitimate police investigation. Once there is a realistic prospect – realistic because based on evidence and not speculation – that the person with whom authorities are speaking may have been associated with the commission of the crime under investigation, presuming that a crime is even under investigation, then the person should be told about the right to silence. See also R v. Worrall, [2002] O.J. No. 2711 (S.C.), at paras. 102-106