Did Superman “Man of Steel” plot synopsis leak online?

By Sean O’Connell A casting call for Zack Snyder’s Superman reboot “Man of Steel” either hints at the film’s plot or simply provides character background for extras who might not be familiar with the classic character. We’re still trying to figure out which is which.
The opening casting call is taking place in Vancouver, and as Warner recruits fresh faces, they released a sheet (obtained by ComicBookMovie) asking for “local people to work as background artists in scenes to be filmed in early October.” The gigs are paid, and some extras will receive speaking parts as filming in Vancouver extends through January 2012.
But here’s the part we find interesting: The description of Snyder’s film … which is beginning to sound more and more like he’s planning yet another origin story for the Man of Steel.

“In the pantheon of superheroes, Superman is the most recognized and revered character of all time. Clark Kent/Kal-El (Henry Cavill) is a young twentysomething journalist who feels alienated by powers beyond anyone’s imagination. Transported to Earth years ago from Krypton, an advanced alien planet, Clark struggles with the ultimate question – Why am I here? Shaped by the values of his adoptive parents Martha (Diane Lane) and Jonathan Kent (Kevin Costner), Clark soon discovers that having super abilities means making very difficult decisions. But when the world needs stability the most, it comes under attack. Will his abilities be used to maintain peace or ultimately used to divide and conquer? Clark must become the hero known as “Superman,” not only to shine as the world’s last beacon of hope but to protect the ones he loves.”

While that could suggest Snyder plans to reboot Superman with an early story of the hero accepting his identity, I’m betting this is just a description to let people know the character’s back story in case they’ve been living on the planet Krypton this whole time and have no clue who Superman is.
There’s no way they’d let the plot synopsis slip in a casting call, which they knew would arrive online … right?