Yes; I know. But similar to tracking a wireless client by MAC address, it could be possible to enhance the system to assign single-use identifiers to flight plans such that it would be radically more difficult to casually associate tracking data to specific aircraft in realtime. I'm not advocating for any change necessarily; just pointing out that RF emissions of a modern aircraft do nothing to belie its identity. The registration information itself is irrelevant to tracking the aircraft movements.
