It might be a gamble, but it's not really that much of a risk. It would only be a risk if it was a given that the F2012 is likely score points based on its pace alone, and that's just not how it is right now. So, why not go for a wet setup and pray for rain, in which case a victory is possible?
That said, it's hard to tell by looking at the qualifying times if they've indeed opted for a wet setup. The 1.5 second gap to pole would seem to indicate a wet setup; that is, if Fry was forthright in his assessment that the car is 0.8 seconds from the front.
But, Rosberg's 0.5 second gap ahead of P2 - which is about the same as his gap to Schumacher in P3 - and the nature of the Mercedes Daffy Duct, his time could be an outlier that's not reflective of his car's race pace. That would imply that Alonso's gap to P1 is closer to 1 second, not 1.5, and that would suggest a dry setup.
Meh. I've probably said too much on the subject anyway. We'll see tomorrow.