Reading through Android's documentation for android:configChanges, I find:
"touchscreen" The touchscreen has changed. (This should never normally happen.)
"navigation" The navigation type (trackball/dpad) has changed. (This should never normally happen.)
Umm.. OK. So what does 'normally' mean here? Does it mean it does happen at times? Could someone give an example as to when this would trigger?
I'm sure @Rafael T is right. It all can be attached via USB. Or maybe in case of emergency it can be replaced "on a fly" by device repairer (with opened case and turned on device..) At least that's how I imagine