Tens of thousands of Britons are being covertly tracked without their consent in a technology experiment which has installed scanners at secret locations in offices, campuses, streets and pubs to pinpoint people’s whereabouts.

The scanners, the first 10 of which were installed in Bath three years ago, are capturing Bluetooth radio signals transmitted from devices such as mobile phones, laptops and digital cameras, and using the data to follow unwitting targets without their permission.

The above mentioned is the United Kingdom (UK) situation, now look at the United States(US) situation:

Departments of Transportation around the United States have deployed
“little white boxes” — Bluetooth detectors used to monitor traffic
speeds and activity. While they’re supposedly anonymous, they detect a
nearly-unique ID from every car, phone, and PC that passes by.

“In this
presentation, I explore the documentation on these surveillance systems
and their capabilities, then build a Bluetooth detector, analyzer, and
spoofer with less than $200 of open-source hardware and software.
Finally, I turn my own surveillance system on the DOT’s and try to
detect and map the detectors.” – Grant Bugher