We risked running low on fuel today, and saw the car sputter briefly while going up a hill. Made it to the gas station fine, in fact with a gallon to spare, it seems.

I presume the gas lines in this car drain from one low spot in the gas tank, but when it's on a slope and very low, there's no fuel there. Why can't we have a series of drains at both back and front (and even all 4 corner points.) It would have to go down from there to stop air getting into the fuel line from the exposed fuel outlet, which may be the reason this isn't done, since the tank is usually down low for various good reasons. Could a smart valve allow for any hose exposed to air to close so that air doesn't get in the line?

I guess stalling going up a hill might not be the end of the world in most places, since you can go down to a flat part and start again, but in a "U" you would be trapped.