Those "power-free" landings require a collective pitch rotor system.
The volocopter appears to be direct drive fixed pitch so it wouldn't be able to autorotate.
It also presumably relies on counter rotating rotors to cancel out the torques, so loss of motors may require other motors to be shut down to prevent undesirable yaw.
I remain somewhat skeptical of these being practical beyond 5-10 minute fun flights around a field, but good luck to them.
