Let's be honest. Tracking humans is much more sophisticated than you suggest. The eye of sauron as you call it can use every mobile phone camera on the planet. Suggesting that recognition linkage has not been already matured is ridiculous. If I say a word next to someone that has a phone with a microphone it doesn't matter if I have my phone or not. I can be identified through my voice and speech patterns on someone else's device and tagged to my own metadata pool very easily... Why you worried about being tracked?