Even in the worst case of a quadrotor - which can't glide or autorotate or fly with a missing rotor - a 250g one is not going to become a lethal projectile at t

Even in the worst case of a quadrotor - which can't glide or autorotate or fly with a missing rotor - a 250g one is not going to become a lethal projectile at terminal velocity. Even the heavy batteries from larger multirotors seem to survive a 100m fall uneventfully, they just make a soft thud when they land. A softball weighs something like 200g and getting hit in the head with one of those at 85 mph doesn't kill you.