You are giving me a basic lesson on international maritime law and practice. Not entirely needed.
I am asking for factual information about a specific scenario. What flag is the ship flying? I understand all the various instances when it could be flying an American flag but am asking what flag they are actually flying. If you don't know then just say "I don't know." or "I don't know but I will google for another four hours because I was born to google."
So name a single U.S. owned merchant or passenger ship that flies an American flag? Your point is meaningless --- in regards to providing protection to avoid having terroristic countries to seize assets owned by U.S. companies in international waters. Basically this is piracy. The U.S. and other western nations have long standing polices on protecting ships of any nation from unjust seizure. All the way back to the time of the Barbary nations.