I've never been able to understand that rule. My understanding is that it's a 'do no work on the Sabbath" rule that has been in place long before electricity was discovered. I really don't understand how flicking a switch is "work". We used to own a rental property in Elsternwick, VIC. There were a few Jewish people living in the block of flats and we had real security issues with one family who would chock the security door, into one half of the block, open on Saturdays because their friends liked to visit them on that day but wouldn't/couldn't press the outside doorbell to get access. This meant that anyone could access that part of the building and we had troublemakers living in the other part who would regularly damage carpets and other fittings in the stairways. It was a real problem. 😡