If they sell any DVD's early Lucas will be forced to count them as double sales for Star Wars Battlefront II. You've left him no choice... !
I guess they're thinking as with a lot of software, stores get it whenever but aren't allowed to sell it until the release date. They could jeopardize their future relations with the publisher if they violate the agreement, and the person's responsible fired, at least so I hear.
Now I'm not talking some seedy shop front in hong kong, I mean your regular corporate retail outlets. Otherwise they'd get into wars with everybody trying to sell it before the other, running out, etc.
In any case I live too far from Wal-Mart (no car) and don't have time to go shopping just to see. I could call 'em, but I'm too lazy. Think I'll just ask for it for my birthday, since that's coming up...