It is pointed out that so far all theoretical estimates of coherent pion
production off nuclei induced by neutrinos rely on the 'local approximation'
well known in photonuclear physics. The effects of dropping this approximation
are discussed. It is found that in a plane wave approximation for the pion the
local approximation overestimates the coherent neutrino-induced pion production
on nuclei.Comment: v3: comments on pion FSI added, minor corrections; version as
published in Phys. Rev.