Why shouldn't they , after all it IS their system .
Far too many , both individuals and institutions ( not to mention the stupid and the lazy :-\ ) have come to rely on what is, essentially, a tool of the United States Military, they put it up to guide their weapons onto targets, (OK, so their track record of "Blue on Blue's is legendary even with it ), not to make life easier for the rest of the human race, right or wrong, it ain't ours,
from wikipedia
"GPS is owned and operated by the United States Government as a national resource. Department of Defense (USDOD) is the steward of GPS. "
http://en.wikipedia.org/wiki/Global_Positioning_System#Restrictions_on_civilian_use
Perhaps, in light of this, back up procedures , such as basic map reading, should be considered, I'll bet an O.S. map of the local area wouldn't be all that costly.