Like the Hunter, the Jockey's hit detection should be fine on a decent ping server (this video was most likely made playing on a LAN). There's no pounce assist so that it actually takes a little skill to pull off. The skilled Hunters in Left 4 Dead 1 can do incredible pounces consistently.
That was genius! Going behind the tree so the other survivors couldn't shoot him off??? I mean, I know that's what the Jockey is supposed to do, but this is the first video I've seen someone do it effectively! haha...The Jockey makes me crack up! :D