A new and macroscopic demonstration of the Pauli exclusion principle, not in the familiar quantum liquids but in a gas, has been proposed by J.P. Bouchard and C. Lhuillier. Writing in a recent issue of Physics Letters A (116, 99; 1986), they suggest a series of experiments to seek an intriguing new kind of convective instability in dilute spin-pOlarized gases - that is, in gases whose constituent particles have magnetic moments mostly aligned in some preferred direction.