There was one post in this thread saying, in ideal world both in pair can dance with closed eyes.
I had such experience, couple of years ago, milonga after workshop in Hungary, with Laszlo, my favourite lector from Budapest. In was 1am, all windows in ballroom were blinded by heavy curtaines, all light switched off, there was complete dark in the room. Dancing pairs were ready on dance floor and first tango begins. Very sooon every leader adopts first and most important rule - do everything carefully. We exchanged partners after every tango. How? Leaders released embrace and put one hand up. And followers were searching for free hand. No speaking allowed. Next blind tango with next partner. Every next tango without vision control I had feeling like I am building up new sense, I felt couples around me by move of air, slight change of temperature, gentle touch of their clothes, unbelievable.
All this last for 30 min and after we all feeled absolutelly amazed by such new experience. I wish to repeat this again, but have had no chance.