You beat me to the Q-ship analogy... great minds...
Read about the Q-ships in 7th grade or so, a fascinating story that stayed with me.
But this possibility has potential for far greater damage. Any strait, bay, container port...as Mao Tse Tung said, “The guerrilla must move amongst the people as a fish swims in the sea.” Well, applies to schools of container ships as well. Or off loaded in some giant container port here, Europe, South East Asia...
How does one differentiate between a container of high sports drones and weaponized drone swarms?
Scary potential.