Originally Posted by
EXDAC
I think you will find that, even with a blank aircraft registration, your flight can be tracked, and your aircraft identified, by the transmitted ICAO code that is unique to your aircraft.
That's what I thought, too. And while the end-user can change the registration, the ICAO id can only be set by an approved workshop or engineer.
There are lists out on the www that translate icao codes to registrations, too.