Ok, heres an idea:
I expect there are two reasons people get busted for energy use:
1. Higher power consumption, as has already been discussed.
2. Regularity of switching. If you have a mechanical timer, the lights will switch on and off at exactly the same time each day
So heres my idea:
It would be fairly simple to make an electrical circuit which switches your lights on and off at random times. I don't mean completely random, but like, switch on at a random time between 7am and 8am and off at a random time between 7pm and 8pm. I might try to design such a circuit myself, and if I'm sucessful, I'll make a thread about it.