is that really any different than a client asking a contractor to sign a NDA ?
I think NDAs are more about proprietary information, along the same lines of how copyright protection encourages creation. If you're working on the iPhone 5 you can't talk about it to google's phone division. If Apple can't have their people sign NDAs then they'd be less encouraged to invest in smart phones.
But I think the whole BP spill has gone way above proprietary information. When something becomes a national disaster the public has a right to know about anything & everything, short of information that is vital to national security. (IE Air Force one should still have classified security even when visiting this oil spill.)
I think what reporters need to start doing is bringing the statements from BP saying that employees / contractors can talk to the press.
I'm impressed of the wife who did talk to the press & the guy who shared the photos. There needs to be more of that & if these "BP blockade" stories keep running, I'm guessing we'll see a lot more anonymous photos / statements.