I did a test some time back to see if suddenly slowing a motor (active braking) could make a prop fly off. I installed a prop as loose as possible and manually grabbed the motor bell at different speeds. I found that it was nearly impossible to make this happen. Just starting the motors would snug up a loose prop pretty well. Only at the very highest speeds, with a completely loose prop was I able to make one fly off. I also tested the effect of losing one motor phase as would happen with a disconnected wire or ESC glitch. In this case the prop would fly off instantly and consistently even if it had been installed pretty snug. I think this is more likely the cause of many of the prop loss crashes that were blamed on props not being installed tight enough.
At times in this video, the prop looks like it is moving slowly but it is just turning at a rate near the camera's frame rate. At the end of the video, you can see what happens if you disconnect a wire and lose one motor phase. Obviously, this was not a P3 but the physics should be the same.
Nice work. So losing a phase causes much more rapid motor deceleration than grabbing the motor, or does it produce some kind of vibration that is more effective at loosening the prop?