How would I disable rotational tracking?

I don't know of any legitimate reason you would want to do this (so I strongly recommend you DO NOT actually release a demo doing this). However, if you really must for some odd reason, you can do it like this:

In OVRCameraRig.cs, at the top of the class around line 59 add:

public bool disableOrientation = false;

Then on UpdateAnchors() around line 106 change it to check the bool:

if (!disableOrientation) {
	leftEyeAnchor.localRotation = leftEye.orientation;
	centerEyeAnchor.localRotation = leftEye.orientation; // using left eye for now
	rightEyeAnchor.localRotation = rightEye.orientation;
}

Then go into the inspector and on the OVRCamerRig check the "Disable Orientation" button.

I have my reasons ;)
Thanks for the help, works great.