The reg which prevents the radiation of one's GPS position is the totally bogus and artificial piece of junk regulation from EASA whose "experts" invented the distinction between
Elementary Mode S and
Enhanced Mode S.
Elementary Mode S is required on 99% of GA, but also the said GA fleet is prohibited from having Enhanced Mode S.
Yet a stock GTX330 will radiate what amounts to Enhanced Mode S, straight out of the box, simply by connecting various GPS etc signals to the back of it. An installation with those signals thus connected (which would be the installation default anywhere else in the world) is illegal in EU airspace
What this means is that most visiting aircraft are radiating all the extra parameters anyway. It is basically just EU based avionics shops that are "not supposed" to make those extra connections
If it wasn't for this stupid ban, a large % of GA (as they use a GTX330) would now be radiating their GPS data, which could be picked up by any suitable receiver, anytime they are pinged by ground based radar.
This is not quite ADS-B which is a continuous transmission of the stuff, but is effectively the same thing in the European context because there is virtually constant SSR coverage.
I imagine that somebody is now pressing EASA to change this ridiculous regulation which serves no apparent purpose. The GTX330 installation manual does not even contain the words Elementary or Enhanced. It is a purely EASA invention, which they did without looking at the hardware actually on the market