With regard to thinking that visual contact with the ground/ horizion would over ride vestibular jumbolation, I suggest that anyone who thinks that getting vertigo can be " cured" when that picture is re-established seek out the nearest Barany Chair, often associated with physiology of flight instruction. After a spin in that, a good instructor can make you feel like the world is spinning, in multiple directions, while you are looking right at it. The creepiest thing is looking at the persons eyes as they are trying to regain some semblance of normalcy. They are uncontrollably flicking back and forth like a couple of pinballs. Unusual attitude training with foggles or a paper bag over your head ain't nothing until you've seen how bad spatial disorientation can actually be.