It really doesn't matter if I don't know the paragraph eight of rule one hundred and thirty four, I know that if you can't do something without poisoning people you should not get to do it. That's as much as there is to it, and it's an argument you can't ever win without proving lead is harmless or something.

You can't just run piston engines on jet-a but you can run them on regular high octane from any regular gas station or any of the actual alternatives, my point was you can swap them for small turboprop powerplants and run the plane on jet-a. Afaik reducing knocking is not really the point of avgas either, which I'm sure you know, but vapor lock at high altitudes, which you can easily avoid by... not flying high, which by your own point is the main use case for piston aircraft. I guess we'll just spray lead over everyone instead, cause it's "safer".