I posted this on Linkedin earlier to a post with more pictures of the aircraft used being shown at a press briefing:
The type of flight computer and GPS unit is the best available to the average person on the street, is open hardware and so far hasn't been copied by the Chinese hobby suppliers. It uses community based free firmware which is pretty good in the right hands Even though it looks pretty low tech, I suspect it cost about £500.00 including the munitions which look to have plastic (3D printed?) bodies. The other photos show an FPV camera which would have been transmitting probably in the 5.8 or 1.2 GHz range. My worry is that this will drive punitive restrictions to prohibit the very very vast majority of users in favour of stopping 1 or 2 bad agents. However, the most effective way of stopping this type of attack is to limit the availability of hardware such as IC hobby engines (including chainsaw and other power tool IC engines) and electronics. The electronics seem like the best approach as you can force the user back in to having to have an RF link.
The thing is, RC aircraft have been used in the past, this is just applying the available technology. I saw on one page on LinkedIn not too long ago a picture of a Phantom quadcopter with homemade 40mm grenades ready to be dropped from it in Iraq. Just new tools.