Ask HN: Special Celluar Network for Defense Contractors?

i was just looking at the specs for Boeing's Black Smartphone http://www.boeing.com/assets/pdf/defense-space/ic/black/boeing_black_smartphone_product_card.pdf

and this really Stuck out:

"Boeing Black has a dual-SIM capability that enables users to switch between government and commercial networks."

So are defense contractors etc. using a separate cell network?