  We study Unruh effect for a wide class of non local theories. Using the
approach of Bogoliubov coefficents we show that Unruh effect remains entirely
unmodified in these theories. However, for those non local theories which
incorporate a minimal length, the approach using Unruh-DeWitt detectors
predicts a modification in Unruh effect. Previous work shows that this
modification may even be drastic. This appears contradictory, with two
apparently equivalent methods giving different results. We investigate the
origin of the contradiction and show that for these theories, the two methods
are indeed inequivalent. We argue that the detector method incorporates an
assumption of local interaction that does not hold for non local theories and
therefore the method of Bogoliubov coefficients is preferable.
