The closest thing to a USB hub I've got is one of my external drives for my Mac Mini has a built in USB hub so I can plug stuff into that as well as directly into the computer. The last time I worried about such things was back when desktop computers only had one or two USB ports. Plus, in a DoD situation, I'd imagine that having your own USB hub plugged into a DoD computer would be the kind of thing that could put your job at risk. A friend who teaches at the Naval War College often laments the unusability of DoD IT because of the level of locking down, but any "Why don't you do X?" suggestions have a response of "I'd get fired."
The safeguard doesn't need to be perfect, it just has to be good enough.
If my experience with users holds true, they'll abandon the quest at the first obstacle and the USB will harmlessly sit in a desk drawer for the rest of time.
