I suspect there's too much of a difference in how much LW members know about basketball to get particularly wide participation. For example, I had to look up "March Madness" to figure out what this is about.

Also, there's a significant chance that either people would just copy the odds from Pinnacle, or maybe even arbitrage against it (valuing karma or whatever at 1-2 cents). Or, well, I'd certainly be tempted to =]