Personally (my own opinion), it's like speeding. You know what you're doing is illegal and could result in a penalty. Whether or not you choose to speed is how it rests on your conscience and what level of risk you take. Here, it is possible to reduce that risk by self-reading the meter and offering higher than actual meter readings in the winter, to offset the negative effect on readings during the summer. Clearly there is a risk associated with that because an actual meter reader may appear and you may get told that you have submitted to high a reading. I've never known anyone be fined for fraudulantly paying to much to the electricity company. However, at the end of the day you are breaking the rules that you've signed up to, so you haven't a leg to stand on, legally.