There is absolutely no reason a properly installed propeller blade will come out of the hub. The testing done for checking the clamping strength of the blades into the hub in Part 23 as well as in ASTM standard is way beyond what the propeller will ever see. However, no one can protect a user from themselves. If they over or under torque bolts, don't setup the pitch the same before torque, don't safety wire properly, use the same nylocks over and over again, don't use nordloc washers properly if applicable. All these things create potential failure points. Of course in this case it may be also delamination of the prop blades as well from a bird or FOD strike or from defect
BTW, I have heard of a few 2 blade wood props coming off just the same. No more, no less. Wood expands and contracts with change in heat and humidity and you have to maintain torque much more frequently. When they don't, out goes the prop