Comment by cowlevel

That's why my car doesn't run on unapproved fuels. No way to know the liquid in the fuel tank isn't concentrated sulfuric acid, which would severely corrode the engine, so better not to let it run without a vehicle-manufacturer-authorised fuel. It can't just be a warning because I might skip the warning and then corrode my engine if the fuel tank is full of concentrated sulfuric acid - so it has to be a hard lockout. The vehicle manufacturer charges a 300% mark-up on the fuel, but such is the price for safety!