It's only over here that we had to add "Gravity" to the title to try and minimise confusion. Although I do reckon it would be pretty funny to see some Endurance racers turning up on carbon 29er hardtails in Lycra having misunderstood what it is....... Especially when faced with something like this:
I think a few unprepared guys turned up on singlespeeds to the first round of the UK Enduro series, and left after practice complaining that it wasn't advertised as 5 back to back DH races. Although I've taken my rigid SS down worse than that pic! Not quickly, but it'd be rideable.
I think it's a falacy though that XC racers can't ride quickly downhill though, the average XC racer could probably beet the average weekend warrior DHer down a hill, in the same way a DH racer could probably beat a weekend warrior XC rider back to the top again as the Eduro series is proving.