[The_President]

Not viable for a non-superpower to create and deploy a successful hostile drone, and imagination is cheaper than reality anyway.

Aside from the hostile drone command and launch being found and destroyed, the drone itself would either be shot down by a missile or disabled by a direct energy weapon.

If the drone were to fault on it's own and was designed to float, it will be expensive to retreive it. Cheaper at scale to launch the sensors into orbit or deploy bouys.