In R. v. Mackenzie, 2013 SCC 50 the Supreme Court of Canada dealt with the definition of “reasonable suspicion”:
Officer training and experience can play an important role in assessing whether the reasonable suspicion standard has been met. Police officers are trained to detect criminal activity. That is their job. They do it every day. Sights, sounds, movement, body language, patterns of behaviour, and the like are part of an officer’s stock in trade and courts should consider this when assessing whether their evidence, in any given case, passes the reasonable suspicion threshold. Thus, in assessing whether a case for reasonable suspicion has been made out, the analysis of objective reasonableness should be conducted through the lens of a reasonable person “standing in the shoes of the police officer”. That is not to say, however, that police training and experience must be accepted uncritically by the courts. As my colleague Karakatsanis J. notes in Chehil, “hunches or intuition grounded in an officer’s experience will [not] suffice”, nor is deference necessarily owed to a police officer’s view of the circumstances because of his or her training or experience in the field. Reasonable suspicion, after all, is an objective standard that must stand up to independent scrutiny. In sum, while it is critical that the line between a hunch and reasonable suspicion be maintained to prevent the police from engaging in indiscriminate or discriminatory practices, it is equally vital that the police be allowed to carry out their duties without undue scepticism or the requirement that their every move be placed under a scanning electron microscope.
It will be interesting to see what, if any, disclosure obligations are placed on the Crown when dealing with experienced drug officers. Additionally, one has to be concerned that the Defence has virtually no way to assess the accuracy of an officer past stops without further disclosure. Watch as this issue develops.