Wow, I know that honda will cover the battery if damaged from driving while out of gas. My friend has done it to his 05 civic.

if car gets low on oil a RED light comes on telling to to stop. If you run out of gas you get a YELLOW warning light.

If toyota built the car so that you can destroy the battery by simply running out of gas then I am speachless. How hard would it be to have the car stop when it runs out of gas? The fact that it runs on batteries when out of gas implies that someone created code for the computer for this condition. Someone took the time to ensure the car would work with no gas and just battery power. To me this says that if you use this you are not voiding your warranty.