For those who've never encountered black ice, or even visible wet ice, here's a short description of the experience.

First of all think back to that trick wherein somebody yanks the table cloth out from the full service and nothing is knocked over.

That's just about what happens with black ice. With zero friction your wheels shoot out from under you as fast as a cartoon banana out of it's peel. You don't fall sideways in the classic fashion, but instead almost straight down along your initial course. Often your first realization that your in trouble is when you hit the pavement. Total elapsed time from when the tires first begin to slip to impact at almost 20kph = about 1/2 second, which isn't much time to react (not that it would help).

As for those who say you fall faster, I agree, it definitely seems that way, even if it isn't.

BTW- other than studded tires, or some other traction improving system, there's no way to prepare. Once steering traction is gone nothing you could do, even if you had the skills and reflexes, can alter the outcome.