DJI has gone along way to “Idiot Proof” the Phantom 4. The main protection form the idiot comes in the form of the CSC command being hanged to shut down the P4 in flight. Now, when powering on the Phantom without props or with one missing/loose, the app lets you know about it. A message pops up saying “Motor Idling ( loose or missing propeller)”
Combine this with object avoidance and the other enhancements, DJI have made the Phantom 4 pretty idiot proof.