I would have done a full rant, but why waste the effort.
The ISIS drones dropping hand-grenades? As if that's been bought over the counter. It's not even that hard to design and build one's own. The software is available in the torrents (I checked), parts available from numerous sources, locally or via the 'net, cash or credit. As if anyone keeps track of who's buying these parts. Lastly, you have ROS for running the beast. If you want spiffy, 3D-print the covers.
For anyone that say's you can't, just check YouTube. One of the people I track has done all this on the cheap.