Disable Vive head tracking with OpenVR?

After upgrading to 5.4.0b, the Vive tracking system seems to be embedded in the Camera component - disabling SteamVR_TrackedObject script does nothing, and disabling SteamVR_Camera also does nothing. I would like to be able to manually set the position of the headset, ideally without using the workaround of moving the play area in the opposite direction of the headset.

I understand the consequences of this in regards to motion sickness.

Thanks.

using UnityEngine.VR;

void Update()
{
InputTracking.disablePositionalTracking = true;
}