Aw, c'mon, if you're going to quote me, at least quote me in context.....
I did say "For certified "slow" GA aircraft, operating at their normal altitudes....."
I would not include a glider operating at 30,000 feet in this category! Yes, I do realize the TAS/IAS relationship. For your average single engined, light aircraft flying below 10,000 feet, the TAS/IAS relationship is not going to affect Vne in any meaningful way. Were it to be so, it would be a design requirment that TAS be displayed to the pilot, for the purpose of defining Vne. It was on the Piper PA-31T used to fly at 25,000 feet all those years ago! Not on a PA 28-161....
As this is a thread about spin training PA-28-161, I suggest that dramatic remarks about flutter, TAS/IAS and high performance sailplanes is rather out of place here! Would somome like to start a new thread for this extreme performance discussion?