IF he was serious he would be burning CDs/DVDs instead of using a read-write USB stick. It is tedious, but blank media is cheap and there is precedent (that I'm sure Bruce is aware of): The DoD's own (classified) SIPRNet was infiltrated via a flash-drive based virus back in 2008.
http://www.washingtonpost.com/wp-dyn/content/article/2010/08...