Earlier quoted context omitted.
They wouldn't have to do much tracking, there is a public registry. On another note, during WWII the mere possession of a radio was grounds for execution in plenty of places, let alone a transmitter, but that didn't stop people from having radios concealed in the most ingenious ways.
True enough. My point was, a governing body with the right resources could track down -anyone- transmitting, HAM or not. Those concealing radios to listen, however, are a whole other ballgame.
So that's why the radios were so important, and that's why they were illegal.