>"The FBI can access cell phones and modify them remotely without ever having to physically handle them," James Atkinson, a counterintelligence security consultant, told ABC News. "Any recently manufactured cell phone has a built-in tracking device, which can allow eavesdroppers to pinpoint someone's location to within just a few feet," he added.
Source: http://blogs.abcnews.com/theblotter/2006/12/can_you_hear_me....
I believe (but cannot cite) that this capability became mainstream when E911 & GPS was mandated.
This stuff is a big reason why BlackBerry was so critical to regulated industries and public company execs. PIN messaging on legacy BlackBerry was secure between devices on the same BES, and there wasn't a direct linkage to the user's identity, which made it easy to lower the value of metadata collection.
The fact that BlackBerry designed around this early on leads me to suspect (as an outside observer with an imagination) that mass metadata collection was known by folks in industry back in the 90s.