HIDDEN QUANTUM NONLOCALITY REVEALED BY LOCAL FILTERS - COMMENT

In Section 3 of his paper [Phys. Lett. A 210 (1996) 151], Gisin argues that a ''careless application of generalized quantum measurements can violate Bell's inequality [...] even for mixtures of product states.' ' However, the observed violation of the CHSH inequality is not in fac t due to the application of generalized quantum measurements, but rath er to a misapplication of the inequality itself - to conditional expec tations in which the conditioning depends upon the measurements under consideration.