That "lesson" is irresponsible in so many ways.
If you feel a need to be prepared for police interaction simply write your message and carry many of them with you.
"Dear officer, I regret to inform you that I cannot be of any assistance in your endeavors. Unless I'm under arrest, I wish to move from this place freely and expeditiously.
Thank you".
No negative vibe, no negative body language, no negativity whosoever.
I saw a kid get killed by a police officer AFTER being subdued by many officers, held face down on the ground and cuffed at a train station in front of hundreds of people. The kid obviously was in no position to do any of the officers physical harm, but apparently he was able to provoke the crazed officer to such an extent that resulted in the nut job shooting the kid multiple times.
My point is, don't provoke people who can kill you, even if you think you know them.