2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/90435A suggestion for an observational test of the difference between quantum mechanics and noncontextual hidden variables theories requires the measurement of a product of two commuting observables without measuring either observable separately. A proposal has been made for doing this, but it is shown to be problematic.4 pages. This is a comment on [1] Cabello and Garcia-Alcaine, Phys. Rev. Lett. 80, 1797 (1998), [2] Simon et al, Phys. Rev. Lett. 85, 1783 (2000) (quant-ph/0009074)Quantum Physicstext