Once again, people without knowing shit say shit.
The training police receive is pretty intense, and part of that is your approach to any unknown situation. Key to that is being prepared for everything to go south in a microsecond. It take too much time to draw your weapon and respond if your hand is out waving about in the breeze. You are taught to have it resting on the but of your weapon as you reach the driver's side window during a stop- after touching the trunk with your hand.
You do that in the case you get killed during the stop your fingerprints are on the vehicle to positively ID it. ANY situation could go to hell in seconds.
Better to be prepared than dead.