ya, you say liao, THE CAMERA thinks the exposure is right.
but more than often, people do compensate to get their desired effect.
anyway with auto ISO, everything will be on 0EV, however you adjust the aperture and shutter speed.
of cause you can adjust the settings to force the overexposure, ie bright daylight, f2.8 + 1/500s. even with auto ISO(with 100 selected), 1/500s will result in overexposure. so you tweak from there to achieve the amount of compensation you want. but it will be very tedious, as you need to customises the setting to different conditions. and it is not always you can get the auto ISO to 100, to force the compensation(overexposure in this case).
i know it sounds confusing, but sometimes i do just that to overcome this shortcoming.