As Diagnostic said,
I politely disagree that it is so clear-cut. If you make the machine complex enough, and add in human imperfections, then you could get a man/machine interface which will be OK for some people, some of the time, and fail to "get through to" different people or at different times. IMHO that would be, in part, a machine (design) issue.
Yes. The original idea that set OC off on this vector was the suggestion that UAS be an aural warning. No, they "shouldn't need" that, BUT!
If I'm sitting in the back doing my knitting, I want
every possible chance of surviving
any unprepared pilot's mistake. If they didn't recognize or respond correctly to UAS, maybe they would have done if the airplane had shouted at them.
Back to Swiss cheese: should we not plug
every possible (known) hole in it? As someone already pointed out, the closing of any one hole in the Swiss you-know-what may have prevented this horrible crash. If it costs $$$, well, I don't really give a
.