It should be trivial to add imho; they are tracking in 3d; so chaperone could also watch in 3d; it's just that they don't...

The Lighthouse boxes are supposed to be aimed at a downward angle. I think that limits the ability for the Vive to track any kind of height past a certain point. Unless they did a calibration similar to the floor calibration where you hold the controller as high as you can and it just sets that as the de-facto "ceiling", there might not really be a way to do this reliably without additional Lighthouses.

I think they added it, actually.

The chaperone doesn't help if you're a noob--you drive your controller through the wall regardless of the chaperone. You get used to your room after a while and it stops happening.

Some people would always see the ceiling grid, which might lower immersion.

That's a good point, and something my Vive setup has been struggling with. My play area is just a little bit too small, so I see the boundaries a lot. It's not as bad as not having them and periodically punching a wall or walking in to the couch, but it's kind of a bummer to see it and go, "oh, right, I'm in my living room," especially in some of the much more immersive experiences.

You should be able to turn it off then, much like how you can change the wall pattern on the chaperone and turn it off completely if you desired right now.

It should track the controllers; not your head; only if you're always with your hands at shoulder/higher level...