That might be workable with a kamikaze drone... if a person could actually detect them incoming... but traversing that short "in range" distance at 45mph+ (just the simple commercial sport drones) and capable of looking down your shotgun barrel while they zig and zag... you better be lightning quick and a crack shot.10ga 3.5" semi auto 28" barrel hot #4 shot should mess up anything within 100yards and any infantry dude shouldn't have any trouble shooting a properly designed gun.
Surveillance and pineapple droppers... I'm sure they have already figured out safe operating altitude to avoid shotgun and other small munitions fire.
With the optics system they are working on... that's one of the issues I think they'll run into. You might see it on your screen, but it won't take the enemy long at all to figure what safe altitude is. Even the most basic and cheap off the shelf drones can fly a heck of a lot higher than most standard infantry rifles can shoot with effective accurately.