Wouldn't surprise me at all if there's some truth in it. I'm sure, on the basis of personal experience, that we are semi- or sub- consciously aware of many environmental cues and signals that aren't generally recognised as normal sensory input. They often go unnoticed because we aren't aware that they can exist - and then something happens to make us aware. Uneasiness before earthquakes is one fairly common example, awareness of imminent changes in the weather is another - and both could be electromagnetic.
On the other hand, I don't think it's terribly important - not even as important as the difference between colour-blindness and normal vision.