Regardless, after the Lusitania sinking, in 1915, Wilson warned the Germans to allow American ships to sail freely on the atlantic. In 1917, the Germans declared all-out warfare on all ships on the Atlantic, regardless their flag. Wilson responded by cutting diplomatic ties to Berlin. Germany followed that up by sinking several American ships, including a hospital ship bound for Belgium. So what were we supposed to do?
Yes, Wilson demanded that Americans be allowed to ride on British ships carrying munitions through a declared war-zone. He also demanded that armed American ships be given the right to sail through the war-zone. Wilson was far more critical of the German's submarine warfare than he was of the British blockade which was a direct attack on innocent civilians. The German policy was too shoot any ship they saw, and they warned all neutral nations that they would not be able to differentiate between neutral and belligerent nations.
"All the waters surrounding Great Britain and Ireland, including the whole English Channel, are hereby declared to be a war zone. From February 18 onwards every enemy merchant vessel found within this war zone will be destroyed without it always being possible to avoid dangers to the crews and passengers.
Neutral ships will also be exposed to danger in the war zone, as, in view of the misuse of neutral flags ordered on January 31 by the British Government, and owing to unforeseen incidents to which naval warfare is liable, it is impossible to avoid attacks being made on neutral ships in mistake for those of the enemy." - German response to British blockade
What Wilson could have done is tell American citizens that they travel through that war zone at their own risk, and a Resolution was proposed in Congress to say just that. However, it was defeated.