I believe that is hard coded so that you don't auto start and then end up with a dead out of fuel vehicle in the driveway... as well as -
Running down low adds heat to the fuel pump and shortens its life expectancy! (being submerged in fuel is its coolant. - even test firing a dry pump will ruin it in less than 5 seconds!)
J Wm Bishop EA, ASADE
The Jeep wave - it means nothing. Now I look for the RearView wave. Anyone can cause a guy to readjust his rear view at night. But in the daytime when you roll up behind someone and they adjust their mirror to frame your Jeep straighter - THAT'S a compliment!