Re: Gawd/ess.
"Sneaker net is always an option and if someone's sole job is to move data from one network to another then so be it."
Stuxnet punched right through sneakernet and into a secure network - then it got out to the wild.
As far as the kind of damage described goes I can think of a dozen overgrown skiddies who'd happily pull this kind of stunt simply for the lolz.