Even if everyone filled up this way, the policy would still be counter productive. Since gas stations are less common, instead of being able to fill up when you

Even if everyone filled up this way, the policy would still be counter productive. Since gas stations are less common, instead of being able to fill up when you are at e.g. 1/4 of a tank, you fill up when you are at 1/2 a tank. You spend more energy visiting gas stations (idling, decelerating) and use more energy carrying more fuel.