Anybody heard a good explanation for why the roof is open?  My first reaction when I heard, during game one of this series, that the Snakes had left the roof open even though it was 100+ degrees, was that they were hoping to disadvantage Matt Cain as a notorious fly ball pitcher.  And then it was open again last night, and the box records the temperature as being 106 degrees.  What's the purpose of having a roof and air-conditioning if you are going to have it open in 100+ temperatures?  I suppose having it closed during day games (when it's probably 120 and with some fans sitting in the sun) still serves the purpose of avoiding the unpleasantry of fan heatstroke deaths but even without the sun you'd figure you'd want to use the roof.

I looked online for commentary or explanation, but didn't really find any.  Found this article re the 2001 World Series suggesting that Sandy Alderson was concerned about the Snakes playing games with the roof:

http://amarillo.com/stories/102901/spo_wsnotebook.shtml

And this article indicating that they were thinking about a humidor before this seasons started!

http://www.azcentral.com/sports/diamondbacks/articles/2011/02/03/20110203heat-index-arizona-diamondbacks-humidor.html

Maybe I'm making much ado about nothing and the Snakes just have a policy now to leave the roof open for every night game.