Another way of saying this: we're good at sensing the delta of acceleration, not the absolute acceleration. Also, we tend not to notice small DC values of either acceleration or rotation, so you can manipulate the user's perception.

Someone published a similar hack for full-room VR, showing you can 'bend' someone's trajectory, to create the false sense that they're walking straight when in fact they're curving. In a large enough space you could simulate an infinite hallway (by having the user walk in a circle).

Sorry, I tried but can't dig up the link right now... but it's out there somewhere.

Let's say I want to simulate acceleration going forward. First, there's the burst of forward motion provided by the cable rig, and that can be > 1G. By also gradually flipping the person onto their back you can simulate continued acceleration of 1G because lying on your back feels the same as 1G of acceleration forward. The VR rig would still show you accelerating forward. I am guessing that if the rig also slowly moved back to its original starting point the user wouldn't notice.

I think hes saying you accelerate forward then tilt back to let gravity help out.