you're talking out of your rear yet again. The whole "embargo" on Smallville was lifted once Singer came aboard SR right before Smallville went into Season 4. Singer, Dougherty and Harris are all good friends with Millar and Gough, and they came to an agreement about working together and the studio pretty much leaves them alone now as far as Superman is concerned. Gough just basically reaffirmed that point in the interview he just did. There's a thread that Pickle-El started with that in it, if you need to read it. The thing with Snow was back long before Singer came aboard. Since Singer and Ottman decided to use the Willaims theme for the movies, the show now stays away from it for the most part.
Think about all of the expanded Superman villains they've used the last two season that they never had access to before, the Fortress of Solitude, etc. Hell the show now has their own version of the "S" shield now, that's the definitive logo of Superman, the logo that makes the costume.
Batman is a different animal all together. Different creative team on it completely, so anything involving that character they have to go to the studio since they dont have a relationship with Nolan and Co. Although if the Comics Continuum article from yesterday is correct, that rule may be getting bent as well later on this year.