A gadget made for runners could become a dangerous tracking device, three student researchers at the University of Washington have concluded. A $29 Nike+iPod Sport Kit, intended to measure runners' performance, could be misused by thieves, jealous boyfriends, or other stalkers, the researchers declare in a new report, "Devices That Tell On You". "When people buy a toaster, they know it's probably not going to blow up when they plug it in," one researcher said in a press release . "But when they buy a consumer device like the Nike+iPod kit, they have no idea whether the device might enable someone to violate their privacy." The researchers suggest that users turn off the kit--which has a chip in the shoe that emits signals--when they are not exercising.