The iPhone's proximity sensor disables the touch screen when it is near your head. Sounds dicey, but in practice has worked nigh flawlessly since launch. The i

The iPhone's proximity sensor disables the touch screen when it is near your head. Sounds dicey, but in practice has worked nigh flawlessly since launch. The issue here is buttons that you physically press down (like the iPhone home button) vs buttons that are an extended part of the touch screen element (the back button on most Androids).