In my experience from when I used to run a game retail store. The games would ship out on Tuesdays and be available to purchase in store on Wednesday. Unless it was a big title (such as this one). In that case, the stores in the states have more than likely started receiving their initial shipments last week and will continue to receive copies throughout this week and are holding those shipments until street date.
Won't Change This Sig Until Jack Thompson Is Brutally Beaten To Death By Kids "Under the Influence of Violent Video Games."
It's because Tuesday is the usual release day for games in the land of burgers, in the land of crumpets and almost everywhere else, it is Friday. SPP wanted to do a worldwide release to prevent spoilers, other developers have done similar worldwide releases as well.