Can Hall drag be observed in Coulomb coupled quantum wells in a magnetic field?

We study the transresistivity rho(21) (or equivalently, the drag rate) of two Coulomb-coupled quantum wells in the presence of a perpendicular magnetic field, using semi-classical transport theory. Elementary arguments seem to preclude any possibility of observation of ''Hall drag'' (i.e., a non-zero off-diagonal component in rho(21)). We show that these arguments are specious, and in fact Hall drag can be observed at sufficiently high temperatures when the intralayer transport time tau has significant energy-dependence around the Fermi energy epsilon(F). The ratio of the Hall to longitudinal transresistivities goes as T(2)Bs, where T is the temperature, B is the magnetic field, and s = [partial derivative tau/partial derivative epsilon](epsilon(F)).