If the battery is completely drained (you can't being it to zero - charging a totally discharged lithium cell can result in an explosion, so if you could discharge it far enough, there's a safety "fuse" that blows and disconnects the battery from the world - permanently), there's no guarantee what the hardware will do, because it's probably between on and off states all over the place - so it could be anything. It's why we turn electronic devices off the way they were designed to be turned off - there's no way to tell what will happen if you suddenly shut the power off. (In most cases - do that to a mainframe computer and you have a few million dollars of junk.) Pulling the battery in a cellphone is a measure of desperation, but it's still not as bad as letting the power slowly drop to nothing. (At about 3 volts, the phone isn't working - but it's not off - so it can be turning lights on and off at random, writing all over storage ... anything physically possible. Try to charge when the battery gets down to about 40% minimum for maximum battery life.)