Yes. Pinging is the audible part of pre-detonation. Pre-Detonation is what we call "knocking".
If you can't hear it, then there isn't really any occurring. This is because pre-detonation is pretty intense explosion occurring at the wrong time in the combustion cycle.
And as for non-audible.... I get what your saying, but look at it like this: Explosions, which is really what gas engines are... controlled explosive devices, are LOUD and you can hear it.
As for longevity, this is where I was pointing to some pretty serious research. I am all about actual evidence. I hate anecdotal evidence. Every peer reviewed article I have ever read has found little issue in longevity, due specifically to that fact that the engines are designed to run multi-grade fuel.
Car makers have for, at least, the last 30 years since the move to EFI and computer controlled timing...designed their cars to operate on all commonly available fuels.
As for additives.. I won't say that their isn't any. There are countless fuel makers, and they all have their own proprietary blend of additives, but again, I have never seen anything from regular to premium other than the anti-knock octane rating.
Chevron, for example, puts "techron" (its engine cleaner additive) in all grades I believe.