https://chroniclingamerica.loc.gov/lccn/sn83030214/1918-03-31/ed-1/seq-1/

Drastic orders have been issued to all military personnel to share no information about troop movements and locaitons. Suspicion is focused on anyone asking any questions about cargoes, departure dates, numbers of troops, embarkation ports. The German advance at Verdun and Amiens is reported as having been halted.

Source: "United States Soldiers Given 'Silence'Orders," New York Tribune, New York, New York, March 31, 1918. Page 1, Column 4.