Not just that. Aerial fireworks being shot, some of which go a good few hundred feet in the air, I've seen. Didn't know when parts of PHX and TUS all of a sudden became night one of Baghdad, when I'm working urban calls.

But seriously though, when working a ground support search operation, nearly all the attention of the helo observer is on the ground situation, whether visually or in using a video camera/FLIR, as well as doing all the tactical coordination over the radio. The pilot is busy with maintaining the orbit the observer needs, coordinating with ATC and/or helo common for traffic avoidance, and avoiding hitting the ground, but more importantly not hitting things attached to the ground such as wires, structures, cell towers/poles, and other towers that aren't easily seen. The time available to look for and avoid some tiny drone is minimal at best, and if one of those goes through the rotor system.....especially the weaker tail rotor....it could be disasterous.