Using radio spectrum detection methods is probably effective against the script kiddies of the drone world, but to sell the idea that this could defend motivated, funded attackers, operating with murderous intent, feels like The Illusion of Safety and a heaping spoonful of snake oil at best.
Serious combatants will not be using wifi/cellular 4G LTE drones they bought off the shelf at Best Buy. Or, I mean maybe they will be in the picture but as decoys, why not?
The point being, that obviously a kamikaze DJI drone is some simple simon nonsense, and I would not bet my life on a team of corporate product managers selling some agile/scrum developed MVP product line that relies on sniffing for consumer band radio telemetry.