blindness from fine bloove vessel bursting
not to mention the tech will be sold to terrorists who will deploy a dirty non directional version.
Imagine a shopping mall full of people which gets locked.
also, would metal shield a person?
Maybe Big Brother will mount heat rays on these at full size. Or maybe, machine guns.
Remember comrades, a police state is a safe state, and if you have nothing to hide, you should not mind an observation visit from a friendly quadrotor.
Aggressive quadrotors, part 3