I personally have dealt with it in several cases where, after the fact, a tel-co’s cell phone tower records are subpoenaed and then used at trial to purport to provide a location of the accused (or at least his / her cell phone) during the commission of an offence. My battles in this area have largely revolved around the expertise required to translate this information into something probative for a trier-of-fact. It is sadly common to see crowns attempt to tender a generic “security director” at a phone company as an expert on this subject, when in fact they haven’t the foggiest clue how the data is generated or what it means. In my view, and several court decisions support this view, someone with an engineering background and knowledge of the science behind cellular telecommunications is necessary to give fair evidence on what facts can (or cannot) be obtained from this data.

The question that has not arisen as commonly relates to your query about GPS location. One might argue that the GPS system, which can provide a considerably more accurate location, should be subjected to more rigorous judicial scrutiny before it is handed over without warrant or other statutory authority to police. What is the privacy interest in one’s public location? These questions are not as simple to answer.