This kind of drones are relatively slow. The perimeter around in the president in any exposed situation is pretty large. Any appearance of unidentified flying objects on the scene is likely to trigger an evacuation of any key targets. For the kind of payloads small drones can carry, and with no possibility of changing the target, you don't even need to move the target very far for the strike to be non-lethal.

On the other hand, you could build a cruise missile (essentially a drone) that might be big and fast enough to hit your target. But those date back to WWII, so if they keep the Secret Service up at night, it's a pretty exhausted security detail by now.

Consider the possibility that you just levelled up in a couple of database tables.

You're not serious, right? If joke: funny. If serious: worrying.

Definitely a joke, if you're serious that's even more worrying ;)

Still, people have been lifted from their beds for tweets about such things.

http://www.thesmokinggun.com/buster/obama-twitter-death-thre...

Granted that was slightly more specific threat, but this being hacker news that ggp already has a strike against ;)

Designing a drone that operates purely based on inertial navigation is a good bit harder and more expensive than something that uses an off the shelf GPS device.

It could operate on visual recognition. It shouldn't be too difficult to find three easily recognisable landmarks around the Mall.