skylab,
I thought about that. At one point, when it looked like the grizzly might be reacting to the copter, I pulled back quite a bit.
Nothing I did caused him to stop grazing there - he stayed in that marsh (and was joined by other bears and deer) for the rest of that day, and for the entire next day.
Thinking more about it, the quadcopter was pretty minor compared with the other distractions/annoyances facing the bears there. There were (loud) float planes flying over, boats going by, other animals wandering the same marsh, eagles and crows making racket and diving down and picking up things... I really don't believe the sound of the Inspire was making any difference in the overall sphere of things that would frighten a grizzly. And, grizzlies really don't seem to much care what's going on anyway - unless it's something else trying to eat their food. We saw one charge a deer that tried to graze nearby.
Actually, one thing I like about the Inspire is that it is very quiet compared with other quadcopters I have used. The lower RPM motors/props really help on that front.