I never go out for Black Friday because I hate the crowds and theres nothing that I have to have or else.
Anyways, they asked the same question on the news today since our Wal Mart is open 24 hours. The reporter said they have large pallets with the "specials" on them wrapped in plastic wrap so you can't take them early. The place the pallets around the store during the day before and then at 5am, a worker cuts off the plastic wrap and the frenzy begins.