If VR is ever going to become mainstream, this will need to be standardized and remain immersive. People are NOT going to pay the premium price and go through the effort to set up a VR space just so they can be forced to "teleport" or "dash" or "sprint" or whatever in an un-immersive way. After ruling out a warehouse as a play space or an omni-directional treadmill, there is only one simple way to do this. and that is to track one or both feet. Why this isn't even considered is beyond me, especially since they came so close with the "arm swing" and "head bobbing" methods. Any other method should be reserved for people who have a physical disability or just don't feel like putting out the effort for real VR.