Targeting something stationary at a location known well in advance would be even easier; like say, a podium at an outdoor speaking event. I wonder what speed an inverted drone, accelerating toward the ground, can get up to while controlling its impact location to within a foot. Might be that adding an explosive is largely superfluous in that situation too.
I don't think kamikaze drones are even remotely practical as weapons for assassination. You'll have big issues with accuracy, lethality, and the element of surprise. It could work, but I don't see any circumstances where a hunting rifle wouldn't be a far better tool in every aspect.
