Eh. Detaining David Miranda did what it was supposed to. Of course it's not gonna scare away journalists from doing their jobs. Their idols are often people who brought big news despite govnt opposition.

But the common man, the man that has most opportunities to blow a whistle? They don't want to be detained at the airport, they don't have the protections that journalists do (like, say, having close journalist friends that can get your story out on the same day).

Arresting Miranda does not deter Greenwald, but it might deter other people from following his act.