As if some terrorist person with plans is going to suddenly think " hold on a minute I just need to do my drone test and register and purchase a remote ID device before I fly off to wherever and cause mayhem", I think NOT.
Tackling the wild west in the sky........
https://www.dailymail.co.uk/sciencetech/article-11678681/Drones-soon-forced-electronic-NUMBER-PLATES-police-track-them.html