It's in his (Mitnick's) autobiography Ghost in the Wires. In his telling of the story they put him in a more restrictive environment exactly because of the reason given (launching nukes by whistling into a phone)
At the time people were using whistles to make free long distance calls, so I can understand where they were coming from.
The part I can't understand is believing that phone-whistles are connected to our nuclear launch system and not simultaneously trying to put nuclear missile operators in jail for incompetence.
"Oh the world might end with some whistling? Definitely punish the whistlers, that's where the problem is..."
The Judge in the case was a complete luddite and actually claimed to believe this. I still don't know for sure if she was just saying it, or she was that dumb.
