pr00ne, Seeding the area in advance, followed by remote operations would indeed create difficulties in neutralizing the ground operation. If drones were dispersed in advance there would be a risk of premature discovery. An earlier suggestion of active van deployment however would minimise that risk.
The video clip posted by TEEEJ should silence that some of the countermeasures proposed are wholly unrealistic. The height and speed would seem to rule out the blunderbus solutions. The speed and manoeuvre would present a difficult shot for a snipper.
I see some sources say a good drone can fly at 50 mph.