It seems that Henry Cavill's incarnation of Superman in "Man of Steel" isn't just one hero in a new cinematic DC Universe, he's actually the instigator for all of them to come out of the closet.
Bleeding Cool scored an impressive quote from scribe David Goyer, who is currently in the U.K. doing press, that explains how Superman's announced presence is the catalyst for other heroes to slip into some lycra:
"It is our intention that, in success, this would be the zero issue and from this point onward, possible films could expand into a shared universe. In our world, the Man of Steel world, Zack has gone on record saying that we’re implying there are other superheroes in this world. But I don’t know that they’ve come forward yet.
The idea is that Superman is the first one. There might be people helping people, but not in costumes, and that Superman comes forward and announces himself to the world. In him announcing himself, he’s the one that changes things.
So there's a cause and effect? "Yes, yes absolutely, in our mind." Does this include Batman?
"Well, yes… there’s definitely… I don’t want to get too in depth. Obviously, Zack and I have had conversations… but there would be a cause and effect. And that would extend to the collateral damage that happened, and to what other countries feel about the fact Superman calls America his home. Man of Steel doesn’t exist in a vacuum."