Just had a commercial on TV showing New Vegas at all retail outlets tomorrow on the 21st. No retailer name stated so likely the commercial was made by Bethesda - how funny. I wish I was a retailer of games tomorrow with games not unlocking for another day.
Retailers usually get the game on thursdays or earlier, they just don't put it up in the store. If I pre-buy a game from an online retailer then they will send it on the thursday so I will recive it in my mailbox on the friday.
The most annoying thing I ever experienced in this regard was when Gran Turismo 3 was released in summer 2001. A local store had a bunch of copies out in the store next to a huge sign saying they won't sell any copy until 3 weeks later.