Whale has made a really good point there, you should check the wiring of those power points, its high likely that if every lot has one, then it may be connected to that lots power mains rather than to the common property switch/mains.
Another option is to try and create a by law for the usage of these power points if they are fed through common property. The by law could provide for annual charges to owners who wish to use common property power for their own purposes (similar suggestion to Whales).