The giant piezoresistance (PZR) previously reported in silicon nanowires is experimentally investigated in a large number of depleted silicon nano- and microstructures. The resistance is shown to vary strongly with time due to electron and hole trapping at the sample surfaces independent of the applied stress. Importantly, this time-varying resistance manifests itself as an apparent giant PZR identical to that reported elsewhere. By modulating the applied stress in time, the true PZR of the structures is found to be comparable with that of bulk silicon.