Is it safe to aim the laser at mirror balls?
Aiming a beam at a mirror ball causes multiple beams to be reflected off in different directions from the sphere. Depending on the size of the beam and the size and angle of the faces of the mirrors, reflected beams may still contain a significant amount of energy in them. If you are going to aim onto a mirror ball you must ensure that the reflected beams do not stray into the audience; i.e. aim the laser beam onto the top half of the globe. Only if you have calculated the beam irradiance to be below the MPE, and if the mirror ball is rotating, is it safe to use mirror balls to reflect beams into the audience.
