It is unclear exactly how many law enforcement agencies are currently using this capability, but it is reasonable to say that while resource limitations used to discourage the government from tracking you without a good reason, these constraints have largely disappeared. – Ron Wyden
Police departments no longer have to pay overtime or divert resources from other projects to find out where an individual goes – all they have to do is place a tracking device on someones car or ask a cell phone company for that individuals location history and the technology does the work for them. – Ron Wyden