Having never seen the contents of a national security letter, I wonder what the ramifications would be if you opened it and read it aloud for the first time in

Having never seen the contents of a national security letter, I wonder what the ramifications would be if you opened it and read it aloud for the first time in front of a large (or small) group of people. Or perhaps have it read aloud to you in front of a large group of people. Certainly you can't be expected to know that is going to gag you until you've read it once and by that time it would be too late. Is it worded such that the whole group of people would be gagged? There's got to be some interesting way to circumvent it.