If that was all that happened then there would be no problem.
But the TSA guy filched his ticket to 'teach him a lesson' and thereby caused a lot of unnecessary stress and confusion.
How would you like it if you left your car running and unattended and when you returned found a cop had secreted your driver's license and registration in order to make you sweat?
The author of the article did not deserve some of the crap that the TSA guys shoveled his way.
Leaving a car running and unattended is a crime in my state, and therefore, sweating a bit is better than a night in jail.