FBI is now Spoofing Cell Towers

I usually don't read a lot of attack threads but this one is interesting.  It appears the FBI is now in the business of spoofing cell towers in order to track and log users.  Kim Zetter reported about this in Wired's "Threat Level".  To be honest I'm a bit shocked and nervous that this is being done.  Not only will it capture the individual in question but everyone else in the area that gets bumped to it.  In addition, the FBI doesn't feel they should need a warrant in order to do it.  That's the problem.  Where monitoring activities like this are needed to catch the "bad guys", they should always be done with appropriate oversite and justification.  Without a warrant it leaves it open to abuse.

Evidently, UK has been doing this for a while as well as the Guardian reports.