In the pre-internet past, movie studios didn't really need to worry about the proliferation of spoilers, because the production usually controlled ALL of the distribution of information regarding a film. For example, unless you read "Starlog" back in the 1980s , there would have been no real way for you to know much about a Star Trek film until you actually saw it in the theater. And almost all the inforation found in "Starlog" would have been controlled by the studio who submitted the press releases.
I say that makes no difference. The spoilers are out on opening day. And the week before, because reviewers can't hold themselves back. There's no influence on box office. I don't see any reason for that much secrecy. It's not Apple vs. Samsung, nobody is trying to copy them. Unless they are so confident with their film that they shit their pants because they fear a superior Asylum remake.