Fred_DM: but the SC2 and WoW Starter Editions weren't available BEFORE release, were they? i bought SC2 on release and don't remember having had an opportunity to play before launch day.
World of Warcraft had an open beta though, before the American release. Then a short while later, a European closed beta that you got into if you preordered the game (or maybe just the collector's edition) or were lucky in a random draw.
I preordered the CE and so would have been admitted into the closed beta, but then I got lucky in the draw so I cancelled the preorder to give someone else the chance - when I finally bought the game shortly after release, the store still had barely a handful copies left of the CE and had raised the price with two thirds of the price compared to if I had stood by my preorder (I still bought it though).