quadcopters can be used for bad too... ISIS

https://techcrunch.com/2016/10/13/how-consumer-drones-wind-up-in-the-hands-of-isis-fighters/?sr_share=twitter

"But this week’s attack marks the first time ISIS fighters have turned a diminutive hobby drone into a deadly weapon, the New York Times reports, and it has Pentagon officials racing to respond to the new threat.
The attack is also a problem for commercial drone companies — particularly DJI, the maker of the popular Phantom — which are now facing questions about how their products end up in the hands of the world’s most notorious terrorist group."

Most commercial quadcopters are too small to carry any sized payload.   But like any good thing, it can also be used for bad.  That's just how life is. So, as DJI says, you try to make it hard for the bad.