Wow, OSX automatically goes into DND when mirroring? That's a neat feature. Does that require a connection that allows the mirrored display to inform the Mac th

Wow, OSX automatically goes into DND when mirroring? That's a neat feature. Does that require a connection that allows the mirrored display to inform the Mac that it is a TV/projector? Or will it go into DND any time you use a mirrored display mode, even via a VGA cable where the Mac doesn't really know what kind of device is on the other end of the cable?