Buffet margin is only an issue if you have been stupid enough to climb to max alt when you are very heavy rather than optimum alt which is the norm.
Fly 3, I don't want to get into an argument with you. In my post I mentioned that Buffet Margin
is an issue. I don't think you can dispute that. As FE Hoppy points out,
his type inhibit TCAS Climb RA's above FL340 probably for this very reason.
I would also add that there could be a number of NOT stupid reasons to fly at altitudes above that which may be optimum on the day. Surely also you acknowledge that buffet margins vary widely from type to type, and that it is not necessarily stupid pilots who find themselves flying with narrow margins.
Like I said...it's just an issue, but please feel free to have the last word.