Y'all need to be careful -- that "advice" has been around a long time, and sure enough, yours truly has tried it on two occasions, and I've decided, it's bogus.
The first cop -- a young fellow in rural Ohio was "staking out" a lonely intersection just south of Ohio Northern University in Ada, OH, and it was midnight after an all-day drive and I wanted to go find diesel for the car. I drove south, and didn't see anything, and pulled a U-turn headed back to the school, when I saw the blue lights.
I had plenty of time, and had license and registration out and both hands on the wheel when he walked up, and I had the window cracked just as I had seen on the YouTube.
The cop wanted me to roll down the window, and I claimed I had allergies, and he said he could smell BS when he heard it, and . . . well he let me go BUT . . .
The next time, a newly widened road near me with good sight distance had speeds picked up markedly. Over a rise I saw a bunch of cars pulled over, and they motioned me over too.
I started with the same bit, and that cop -- clearly experienced and wasn't going to play said, "I can force you out of the car and put you in handcuffs, and then we can discuss it. Are you going to roll down the window?" They were using this electronic ticket writer, and the ticket of the day was a non-punitive "failure to obey road signs", and I caved.
I have come to the conclusion that most cops have a job to do, and when it involves me, c'est la vie, and roll with it.