OK I finally looked at the truck in question.
His placement of the flag places it in danger of touching the (dirty) top of the roof, and the fender, as well as the possibility of the wheel well - disaster. It may also be touching the bed of the truck as is.
Again, I’m just talking strict rules - especially the spirit of the rules.
I don’t mean the boy has to be suspended, or chastised, or otherwise punished.
Careful, you are becoming like some religionists...more concerned about the rules than the object or person of veneration.
I could make the case that any placement of the flag outside a hermetically sealed case puts it in danger of being soiled or torn. And I would be right. If I were more concerned about strict application of the code than anything else, I would be right. I think you are getting to that edge when you talk about exhaust swirling around and touching the truck and the possibility of being torn while flapping in the wind.
The SPIRIT of the code is to DISPLAY the flag,not treat her as a fragile snowflake.
The kid displayed the flag with pride and honor, he got the sides mixed up, but other than that he was in compliance with SPECIFIC mentions in the code of proper display. He definitely comported with the spirit of the code.
HE DID FINE.