The hardest parts of a drone are the motor shafts which will be a few inches long and perhaps 5-10mm diameter - they will be made of hardened steel.
Ehhh...no. For the worst case scenario the camera frame, battery pack and lens body are by far the most sturdy and heavy. The most popular Canon DSLR with standard internal battery and memory cards are just over 900g. A 24-70mm lens typically used on the PRAS mounts I´ve seen are between 600 and 700g.
Small stuff with GoPro maybe not so bad, big heavy pro stuff is another matter. And the large drone quoted to be spotted in the London TMA is just the thing that carries that.