Not long ago I got a transponder check on my mode-S for professional purposes, but I take your point. NATS screens see my code, altitude (which could be C, S, or ADS-B), and my position: but *how* they got my position is probably transparent to them.
It is I *think* being recorded somewhere however, which can then be used for prosecutions? And, admittedly not quite what I said, both SE2 and PAW will see ADSB-out.
G