They'd have to get their hands on "hundreds of autonomous drones" and deploy them on site. Seems unlikely for any of the current terrorist organisations.
really? It’s not like this would cost more than 5K usd each. It doesn’t have to be military grade this is not much more than a DJI drone with better firmware and a micro railgun
sure, looking at how they usually conduct business though, it seems unlikely that would happen. but whatever, it could theoretically happen, what do I know.