The cabling radiates like crazy at those frequencies. Interestingly enough, there is enough radiation that you don't really need an actual connection. Someone

The cabling radiates like crazy at those frequencies. Interestingly enough, there is enough radiation that you don't really need an actual connection. Someone put one of the endpoints in a field with a generator and got a connection to another endpoint. In a sense power line adapters are just using radio over the air. Sending data over a power line, even at low bit rates is very difficult to do reliably. So all the radiation is in a sense a feature in that it improves connectivity. Not so much a feature to those who have an actual licence to use those frequencies...