There is a bit of a grey area however when it comes to passengers. What expectation of safety should they have? Tricky one...
Yes, I see your point. I do tell them that the aircraft is 56 years old, and I do give them a safety briefing, but actually I don't think I am putting them at more risk than in a more modern aircraft. If it is that dangerous how did it get to be that old?
As for mode C, eliminating the requirement for those a/c without an electrical system would actually remove a surprising number of potential paints. Gliders, which are rather hard to see, rely on battery power for their radios and varios. So do hot air balloons but they are pretty hard to
avoid seeing even if they tend not to paint on primary radar.
Actually, I do have an electrical system, but as I have got bugger all to look at inside I tend to keep my head out of the cockpit (and I have a rear view mirror, just as well as everyone keeps overtaking me)
Also the passenger gets to help with the lookout, having even less to see inside, once they get bored with the back of my head.
Someone said in another thread that we shouldn't try to solve people problems with widgets. I tend to agree.