The covert cellphone tracking tech the RCMP and CSIS won’t talk about

"“These devices are thus far more covert in operation – indeed effectively invisible – but they can only detect signals of nearby phones when those phones are actually transmitting data,” according to a paper published in May by Christopher Soghoian, principal technologist for the American Civil Liberties Union, and Stephanie Pell, former federal prosecutor and non-residential fellow at The Center for Internet and Society at Stanford Law School."