@m @cstross Drones are a way to convert manufacturing capacity into dead enemy soldiers (useful) and reconnaissance (vital).

It's really unlikely there's an effective passive counter; armour exists to get knowledge about how you fucked up off the battlefield. It isn't ever going to provide a functional counter to reconnaissance.

Aka, drones are expendable cavalry. (That IS new; cavalry is traditionally a scarce, expensive, prestige asset.) All the traditional cavalry things apply.