So why is there so much resistance to making transponder use compulsory - at least in all aircraft with an engine and that wouldn't fall apart if you hit them? That would encourage those who could afford it to fit TCAS, which would also reduce the risk to those who couldn't, by reducing the number of aircraft in the sky relying on eyeballs alone.
What a stupid reply!

.... So what about those who couldn't afford it? no, hang on, you just said that making transponders compulsory would
encourage those who could afford it to fit TCAS, which would also reduce the risk to those who couldn't
... of course it would, they wouldn't be flying would they???
Of course this subject hasn't been done to death recently has it? ... Let's just stick to "what's the best avoiding action"? shall we? ... please!
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