This is one I can speek to with personal knowledge.
My spinner departed my air plane. This left one small piece of back plane of the spinner attached to the prop for a little while.
Don't belive I have ever pulled a throttle back to ideal so quickly.
Only had 1 desire, Please engine stop shaking and stay attached to my airplane. Of coarse at cruise mixture settings and 8500 ft, engine will not ideal at lean mixture so it quits running.
Last piece departed and all ended well. (GPS Nearest function very nice when it comes up 6 miles 5500 ft)
I.E. Loosing a piece of a prop is very very bad. And in almost all cases engine will be shut down at best, and in worst case engine will depart the plane.
HiTech