this is such utter BS. As long as the man is paying his bill it's nobodies business how much power he's using.
I agree with you. However I have to suspect such things became socially acceptable for the same reason school teachers (at least in the US) are required to report domestic violence and other issues (I forget which ones) by law. "Oh, you don't want this to happen, so you have to report it to us!" The power company is likely under similar legislation; though it might just be a wink-and-nod agreement. We live in a police state; it breaks my heart to be unable to love my own country because of this kind of shit. Ok, I love my country, not the people who enforce and write the 'laws'.
I would say that at the very least electric/power companies should be investigating excessive usage. If a customer is using excessive electricity, the most common reason is likely a broken appliance and the customer is essentially paying more then they should be. If the electric company warns the customer of such excessive usage then they can take corrective action. (I know this does actually happen often with water companies, when for example people have a leaky pipe or a leaking toilet)