With a little from my friends (Beijing re-mix)
You can't really make this stuff up: Passer-by pushes suicide jumper in south China. Nor can you improve upon the story. Priceless!
But I suppose excluding the fact that the would-be-jumper failed his mission, this went smoother than in most other places. No one trying to sweet talk you off the bridge or such (yeah yeah, I know, jumper just wanted attention etc... but humour me here).
Now: I can only think of the torture one would face in places like, say, downtown Helsinki. During daytime hours, no one would pay any attention ("better not look; he's drunk, or crazy, or both") whatsoever, and during night time, well, he'd be pestered by dozens of drunk (and possibly a few crazy) asking stupid questions, telling lame jokes and repeating the same at least a dozen times. Then wandering off for a while to resurface a while later to repeat the thing.
And although you might think this latter crowd might be more useful wrt. jumping part -- by sheer act of clumsily bumping someone off the bridge, chances are that a sober suicide-contemplator would be more likely to grasp onto something than the drunken person. So it's quite likely the depressed person might just become an accidental hero by saving a drunkard's life.
That's why suicide candidates in Helsinki never use bridges, or other public places, for this purpose. There are no kind elderly chinese gentlemen to offer a "helping hand".