What is the legal test for an inquiry into possible police trickery?

Unlike the consideration of inducements, oppression and/or the operating mind requirement, the inquiry into possible police trickery is a distinct inquiry separated from the rest of the confession rule. The inquiry into possible police trickery is distinct because of its more specific focus of protecting the rights of the accused and maintaining the integrity of the criminal justice system. (See Oickle, paras. 63 and 65) Despite that important focus, in the context of a court’s consideration and examination of possible police trickery, courts need be very cautious about unduly limiting a required and acceptable level of police discretion, which discretion is indispensible in the course of their investigations of crime and their detection of criminals. That point was aptly made in Rothman v. The Queen, 1981 CanLII 23 (SCC), [1981] 1 S.C.R. 640 by Lamer J. (as he then was) and as cited in Oickle at para. 66: … [T]he investigation of crime and the detection of criminals is not a game to be governed by the Marquess of Queensbury rules. The authorities, in dealing with shrewd and often sophisticated criminals, must sometimes of necessity resort to tricks or other forms of deceit and should not through the rule be hampered in their work. What should be repressed vigorously is conduct on their part that shocks the community. (emphasis added)