Article

I got this from the IMDB News site:

KNIGHT IS IN THE DARK OVER SEIN-OFF

A day before filming the final episode of Seinfeld, even the cast was being kept in the dark about the show's contents, the New York Daily News reported today (Tuesday). Wayne Knight, who plays Newman, told the newspaper, "I know nothing about it. It's a bigger trade secret than anything I've ever seen. ... I don't know if they'll have any documents to sign or make us leave samples of our saliva." Knight said that he did run into Larry David, Seinfeld's onetime executive producer and writer, who is writing the finale. "He says he's very excited about it. ... I think it ties together every human being who's ever had anything to do with the show," Knight told the Daily News.

I didnt think they were filming until 4/9..? But obviously they need to rehearse a few days before. Probably be alot harder to keep the script a secret if everyone is rehearsing it for a week before they film...