Run it twice

[cjmewett]

Anyone care to discuss under what circumstances they prefer to run out turn/river multiple times in an all-in situation? I know this is a reasonably basic question, but I'm curious about the range of responses.

This is prompted by a thread on M/HPNL where lapoker chooses to run the river twice with his baby flush against bottom set:

link (http://forumserver.twoplustwo.com/showflat.php?Cat=&Number=3697791&page=0&view=colla psed&sb=5&o=14&fpart=1)

Here's my question, really: what does the villain have to lose from multiple runs? Half of a pot in which he's a substantial dog? Anyway, discuss.

[The Goober]

There was some discussion about this before (I think the thread used the term "doing business" instead "run it twice", but I wasn't able to find it with a search).

I think the consensus was that its doesn't change EV at all to run it twice (this seems obvious), but it does lower variance. This should favor the player who is currently ahead (as it did in this case), but I really can't blame the guy who's behind from wanting an extra chance to suck out and get his money back. This actually feels like something of a mental contradiction to me, but I suppose it's just a natural risk aversion fallacy.