The sad thing is, that these items don't actually need to be a genuine threat, they just need the media to make them LOOK OR SOUND like a threat, and the hysteria of a gullible public does the rest, and we end up with bans/restrictions/etc that will all be ignored by criminals anyway, and only affect the law abiding.
There are no doubt more practical and accurate ways to kill someone than loading a quad with explosives and hoping to get it into place to do the damage.
In fact, for speed and for silence, I'd say even an RC glider would be a vastly better method, as it would carry more, and make no sound.
But it's not whether drones are an ACTUAL threat that puts the sport at risk, it's the PERCEPTION. They only need to get the public up in arms about them with a few stories about the peeping tom that perves on neighbours with one, a story about the moron that tried to film an emergency airlift helicopter taking off or landing and "nearly caused it to crash", and a few well exaggerated stories by "reporters" giving loads of BS as "facts", and soon you will be fighting bureaucracy at every step.
The radio signals used to control them would be easily swamped or blocked, and a localised high power transmitter sending false GPS signals would prevent pre-programmed GPS coordinates being successful, so if they were ever perceived to be a genuine threat, I'm sure there would be counter measures quite easily set up. Hell, even e perimeter of fine threads around the area your President was going to be, would probably make it damned hard to do anything. Like I said, they're totally impractical as a means of assassination, but that wouldn't get an airing for 2 seconds if the media decide to promote them as dangerous weapons, you'll struggle to have common sense prevail against the hysteria they'll create.
