[daemoncoder]

With the 'no drone left behind' policy, there will be drones to fetch injured drones.

[mabbo]

While I actually agree with your point, I have this image in my mind if a "Simpsons-esq" scene like

"Mr Burns, we've lost 20% of our drones"

"Well then... Send more drones!"

But honestly, if the drones are operating as a swarm then a downed drone could report it's last known location to it's peers for easier recovery.