It's not like that. If the vga cable is not connected, the select pins will not be grounded.Permanently grounding the VGA select pin means you won't be able to use the original AV socket any more.
Yes. And when you connect a monitor, these 2 pins will also be grounded.I think I tried this once years ago and I didn't get it to work. Does it involve connecting the VGA and RGB select pins to separate ground points through the VGA socket and cable? RGB select is obviously still required for the AV socket after all.