Would an announcement of a release date for a game being only a couple days away hurt day one sales or help? Has there ever been a"Hey this game is coming and oh yeah you can get it in two days." type of announcement?
I really doubt that. The best time would probably be sometime in July since I think that month is pretty bare. There are a number of games coming out in both August and September so those would be poor months to release it in.
Wouldn't surprise me if true, at the very least I could see them releasing the digital version instantly after their conference and having a physical version available later in the week or something along those lines.