OK, I already knew those things, but I still don't understand. I get that there is a large electrical potential difference between mains and ground. (I've even experienced it first hand). So why is there no potential difference between a charged battery terminal and ground. Or we could take a capacitor as an example because I know it has a plate that is crowded with free electrons. Do they not want to flow to ground?
You guys say that mains neutral is bonded to ground, and a battery is not. You are implying that the earth ... the soil, rocks, rivers and all that... forms part of a circuit. Lets take a long power transmission line as an example. I don't know exactly how closely spaced the physical bonding points are, but I'm quite certain that in some cases it could hundres of meters to such a point. There could be billions of ohms of resistance in between. And yet, we know that touching a fallen transmission line can kill you. You also imply that if I drive a conductive rod into the ground, connect it to the negative terminal on a battery, and measure the voltage between the positive terminal and any earth ground point, that you will see a potential difference. I have tried this and there is not.