I didn't do the math here, but my intuition tells me that as lasers scatter, if you point a 1MW beam at a rough surface, you'll have a lot of high-power reflections in every direction - even a laser pointer reflecting off a wall is annoying for the eyes. I'd love someone more knowledgable about high-powered lasers to chime in here.

Anyway, neither of those two options seem safe for drones flying just above people's heads. Maybe microwave lasers would be better? Also low-powered visible-light lasers could be enough to blind sensors and force the drone to rely on dead reckoning while not risking eye damage.