It seems logical that this is happening in a lot of places. Access to an AC outlet is not controlled at all in most buildings and anyone can plug in anything.

It seems logical that this is happening in a lot of places. Access to an AC outlet is not controlled at all in most buildings and anyone can plug in anything. A crypto miner with a loud fan might be more difficult to hide, but there are lots of loud industrial spaces with outlets or machine rooms that are loud in most large buildings.