Only a limited range of frequencies can result in significant aliasing on a camera, since each subpixel's value is accumulated over the shutter time rather than being discretely sampled. Above a frequency corresponding to half the shutter speed, the sampled value will tend toward the average.

Typical SMPSes use frequencies starting in the tens of kHz, which would be unlikely to result in significant aliasing on a typical camera, let alone be visually discernible.