Very interesting - I wonder if it's the reverse for countries that drive on the Right hand side of the road?
Logically, that would account for the difference, and so ours would be reversed.
Intuitively one tends to think in terms of "landing on your head" but that appears to be rare, and the "smack in the face" seems to be highly probable.
I read a few accounts where the rider was very grateful for the chin bar. It even makes me a little wary of tip-up helmets, even though they claim their locking mechanism is strong enough.