As long as you are using radio frequency personal device, I guess there is at least one chance that you can be stalked by someone. And definitely, there is no warning at the side of the box as you may see on the drug’s package.
A team of researchers at Department of Computer Science and Engineering, University of Washington releaseed a technical report on the risk of people being tracked by wearing Nike+iPod sport kit. [Full report in PDF]
They developed a prototype surveillance system by plotting Nike+iPod user with Google maps. The detector was created from a gumstix connex 200xm, a wifistix, a gumstix breakout board, a iPod dock connector, and a Nike+iPod receiver. By this means, the real-time surveillance data can be sent via email and SMS. Another means is developing a system that can send real-time data to an attacker’s wrist watch, by using a second-generation Intel Mote and a Microsoft SPOT Watch.
By these means, a person who is wearing an active Nike+iPod kit sensor (regardless of whether iPod is connected or not) can be tracked anywhere. The paper raised interesting example scenarios based on the results from their prototype systems including: a jealous boyfriend, an ex-boyfriend, a professional thief, an unethical organization, customer tracking, and muggers.
Interestingly enough, although turn switch off is suggested to be practice in common, they don’t believe it is enough for several reasons.
First, this approach by itself will not protect consumers’ privacy while the devices are in operation. Second, we believe that it is unrealistic to assume that most users will actually turn their devices off when not in use, especially as the number of such personal devices increases over time.