Another reason for not running a (modern) car out of fuel, other than having to bleed the fuel system, is that if it runs out while you're still moving, you'll lose pressure in the power steering and brake servo's, which could easily catch one out if you're not expecting it.
Are any aircraft fuel tanks baffled? I could see a baffled section at the lowest point of the tank being useful for accurate content measurement, and for placing the fuel pump in an area which should empty last.