You could drop a bunch of BTLE fobs into a disaster zone, and let them tell each other about temperature, poison gas, cries for help, etc. in their vicinity. Each fob triangulates its peers, and that information is passed around too. As additional drones (or people) approach the zone, communication with any fob gives communication with all of them, enabling instant cognition of the situation. That’s a real application now (in theory), but with much more expensive radios. But with drones, the tiny inexpensive fobs can be dropped directly into the hot-zones.