Unintended consequences? The cost of aluminum is going to soar due to increased demand in the auto industry. So the price of everything else made of aluminum will soar, too. Expect increases in the cost of air travel (aluminum in planes), canned beverages and aluminum foil.
Realistically, now. Who could possibly have anticipated increases in the cost of corn when half the supply goes into our gas tanks?
Never mind that aluminum overall soars, the price to fix autos containing the aluminum will jump. Whole parts, especially engines, will need to be replaced and cannot be simply pounded out with a hammer. Previous repairs costing $700 will be $3700. After driving it a few years, folks will simply walk away as they do with houses and the landfills grow and grow.