This makes zero sense:? If you hook a 240V appliance to 12V DC it will draw negligible current. Perhaps you are trying to talk about people using a 12V to 240

This makes zero sense:? If you hook a 240V appliance to 12V DC it will draw negligible current. Perhaps you are trying to talk about people using a 12V to 240V inverter to run AC equipment in a car or off-grid, but not using large enough batteries. What-ever, the end result will be a flat battery or blown fuse, so little damage will be done. No worse than any other 12V wiring in a car.