It's a little uncanny how well people know who is ahead/behind them, even many days walking.
We dropped a digital camera in the Roan Highlands and figured it was gone, but one the same day before we had even eaten dinner the finder showed up at Uncle Johnny's hostel in a car with our camera. He knew us by our description, direction of travel, etc. In our case this was great, but it could also work in a negative way if someone is stalking you for example. Sounds like time for the PCT/CDT/Nepal trek/El Camino use your imagination, there's a lot more to do than just the AT.