Is drinking inside a car not moving an offense?

I was walking past the Municipal Auditorium and inside a parked were two fellas at quitting time enjoying a couple of beers and life a tad loudly.

I did a double take but decided to mind my own business since the car was not engaged. Yet ironically, a city bus passed the the car with a giant ad on it warning drunk drivers that they'll lose it if they booze it.

Now I did not know enough about the law to have challenged the two men or walk across the street to the police HQ. But I am going to Google the topic to get an answer. Because if those guys decided to drive, then I'd be somehow or somewhat responsible ... conscience wise.

If you know the answer to my question, please let me know. Too many good and innocent people have died simply because someone started drinking while they were in their car.